By request here is my examination of Albus Dumbledore and some of his actions and possible motivations thereof.
This essay is quite long so I have broken it up into multiple parts so please bear with me. Also, these are just my interpretations of events as portrayed in the books. They are just my opinions, I respect the fact that many absolutely adore Dumbledore. Also, I only classify the seven books as canon, nothing else. Now to the point of this whole thing.
The Lies and Crimes of Albus Dumbledore
In any crime you have to eliminate the distractions and distill things down to the unholy trinity; motive, means, and opportunity. In addition to these questions are who, what, where, when and why. Herein lie the details of the crime, oftentimes the two important questions that will lead to the person responsible for the crime are, who had the most to gain from the crime? Who had the most to lose if the crime had not been committed? Answer these questions and you will likely have found the guilty party.
There were many, many crimes committed in the Harry Potter story. Many of them by the so called “dark side.” But surprisingly a great many by the light side, and nearly all of them were committed by, or at the behest of one man, the recognized leader of the light Albus Dumbledore. In this essay I examine many of the events in canon with an eye toward spotting inconsistencies and illogical behavior.
We start by examining the events immediately after the deaths of James and Lily Potter. Our first questions are:
1. How did Dumbledore know that the Potters had been attacked?
2. How did he know that only Harry had survived?
3. Why did he send Hagrid, who is not allowed to do magic, to collect Harry?
Hagrid tells Sirius that Dumbledore has decided that Harry is to go and live with his maternal aunt. This strongly suggests that Albus knew from the get-go that Harry was an orphan and he unilaterally made the decision of where Harry would be raised. As for how he knew, he had to have placed wards around the home that would tell him that both James and Lily were dead and Harry had survived. I think that the Potters were set up, Dumbledore knew that they would be killed, and more than that, I think Dumbledore was counting on them being killed. How else would he know that he would be able to quickly assume control over the toddler Harry?
More than likely Dumbledore made the decision to send Harry to the Dursleys long before the child’s parents were killed. Why is this the most likely scenario? Because Dumbledore sent Hagrid to pick up Harry from the ruins. Sending Hagrid only makes sense if Dumbledore knew exactly what had happened and that Voldemort brought no one else with him and that the danger had passed. I think that there were possibly wards to allow Dumbledore to monitor the situation and perhaps let only certain people through. Why wards? Because Dumbledore had to be absolutely certain that no one else was going to be able to get Harry or attack Hagrid. If Dumbledore had the slightest doubts he himself would have gone to get the child. So why Hagrid? The only thing that makes sense is that Dumbledore expected Sirius to show up. With Hagrid there to collect Harry, Sirius would not want to risk a fight and possibly hurt a baby.
So what was Dumbledore doing and why did he not go to the Potter home himself? Well two possibilities, one is that he was there and that’s how he knew what happened. Or that Dumbledore was somewhere that he could monitor something very important to him. Something so important that he would risk what he knows to be the child of the prophecy. The possibilities are that he’s trying to protect something or someone. It can’t be Harry that he’s protecting because he sends someone who can’t do magic to pick him up. I can hear it now, Dumbledore apologists are saying, “he was concerned about what the DE’s were going to do so he was watching them.” Maybe, but if that was the case then surely he would have actually done something to ensure they were punished or I don’t know, maybe actually enforce the laws. No, I don’t think he was watching out primarily for DE activity. The only thing that makes sense is that he is either trying to cover something up or he’s monitoring Voldemort, perhaps both. As for what he could have been covering up I’ll explain that later. But monitoring Voldemort is possible. I think Dumbledore could have gone back to Hogwarts, and perhaps performed some sort of ritual to find out about Voldemort. To make sure that Voldemort doesn’t immediately regain a body. While this is going on he sends Hagrid to kidnap the child and bring him back to Hogwarts.
If Dumbledore had been on the scene then the logical question is why did he leave Harry there and not bring the child to Hogwarts? If he examined the boy and discovered the soul shard and remnants of whatever magic Lily used to protect her son, Dumbledore may have been afraid to move Harry for fear that Voldemort could somehow use the child to come back immediately. Dumbledore might have wanted to return to Hogwarts and do some fast research.
At this point he could have put up some wards to allow only certain people into the house.
The theory is thin but it is somewhat plausible.
Despite what the child’s parents may have wanted or regardless of what provisions they made Dumbledore ignores all of it and abandons a toddler around midnight on the night of Nov 1-2. The low temperature on that night was between -1.6 Celsius or 29 deg. Fahrenheit and -4.6 Celsius or 23 deg. Fahrenheit. Ok he could have put a warming charm on the blankets, but I doubt it. There is no mention at all of any warming charms or any spells designed to keep a toddler from waking up and wandering away. The sun rose at 6:55 the next morning that means that a baby was left on a doorstep on a cold night for at least 6 to 7 hours, if not longer.
Think of that for a minute and substitute the names Albus Dumbledore and Minerva McGonagall for Cornelius Fudge and Dolores Umbridge, or what about Lucius and Narcissa or Voldemort and Bellatrix. Is it wrong to abandon a baby if it’s someone other than Dumbledore and McGonagall or some other so-called “light” witch and wizard? If so, then it was wrong no matter who did it.
I think it’s unlikely that Dumbledore was ignorant of the switch in secret keepers. I think he was probably the one who performed the fidelius charm. Because I don’t think he intended to protect James and Lily at all. Why do I think this? Because in Snape’s memories that he gives to Harry, it shows Snape going to Dumbledore and begging him to protect Lily. Dumbledore doesn’t act surprised at hearing Voldemort is after the Potters. Nor does he act in any way concerned for them. What does he do? He starts negotiating with Snape. He asks Snape “what will you give me in return?” Now think of that for just a moment, when told that an evil wizard is going to hunt down and kill two of his former students, his comrades-in-arms, members of his very own group dedicated to bringing down Voldemort, Dumbledore’s reaction is to negotiate something in return for protecting the Potters. In essence he is telling Severus he’s not going to lift one damn finger to protect his own people unless Severus gives him something in return. I can’t begin to describe how reprehensible this is. It shows Dumbledore to be the monster that he is. He has to be bribed to do something he should have been doing already. When Harry saw that memory he should have said screw this. To my mind this strongly suggests that the whole thing was a set up and Dumbledore intended for them to die.
I think Dumbledore probably talked the Potters into leaving James’ ancestral home, probably citing that the home was well known. I think it’s likely that he hid the Potters in his own family’s former home. He would have wanted to leave as little as possible to chance. The whole thing was too convenient, there were far, far too many coincidences, it was a perfect storm.
The Potters had been hiding for a whole year, which means that they were probably hiding somewhere that was very secure. It’s likely that place was the Potter ancestral home. Somehow Dumbledore talks them into going to hide in a cottage in Godric’s Hollow. He also talks them into the dubious security of the Fidelius charm. I think Dumbledore was probably the one that told them that someone other than themselves should to be the secret keeper. It makes absolutely no sense to not have been their own secret keeper. We know that the secret keeper can live in the protected property because Ron tells Harry and Hermione that his Aunt Muriel’s home and Shell Cottage are under the Fidelius and that Arthur and Bill are the secret keepers. So the only reason for having someone else to be secret keeper is if someone wanted that information leaked to Voldemort. Who would want that? Someone who wanted the prophecy to be put into play. Then barely a week after the Potters go under the Fidelius charm they are attacked.
So what is Dumbledore's motive? He wants to defeat Voldemort in a way that does not compromise information that Dumbledore doesn't want exposed. He knows Voldemort is winning and it’s only a matter of time before the Ministry falls. He is desperate, he has to do something so that Voldemort will activate the prophecy. So he talks the Potters into going under the Fidelius at his old house. I think he also suggested using Pettigrew to either the Potters or Sirius or both. He needs that info to get to Voldemort, he can’t use Snape so he uses Pettigrew. You can’t tell me a Master Legillimens didn’t know who the mole was.
I think Dumbledore was there that night, watching. I think it likely that he was the first person on the scene. I think as soon as Voldemort vanished Dumbledore went to immediately examine the scene. He probably did some heavy diagnostics over Voldemort’s robe and wand and Harry. I think he knew from the first that Harry’s scar had a piece of Voldemort’s soul. I think he could have dealt with it then but chose not to because he wanted to see what use he could make of that later. I think he knew all along that Voldemort had used horcruxes and that he also knew Tom made more than one. I think he had been collecting those memories about Tom for a very long time.
4. Why did Dumbledore go to such great lengths to hide vital information from everyone who might have been able to help bring down Voldemort?
5. Why would he place the full responsibility for finding and destroying the Horcruxes on three young people when he had a number of people he could have safely informed and who could have helped?
Dumbledore’s actions do not make any sense unless he was hiding something. Specifically, if he was hiding evidence of his own wrongdoing, something that if known would absolutely destroy his reputation. I think he relied on naïve young people because someone with more experience might have caught an inkling of what he was doing. Especially someone like Amelia Bones or the Unspeakables.
What I think what Dumbedore was hiding is that he had been using Hogwarts as a social experiment. I think he was trying to prove to himself that a Dark Wizard could be redeemed. I think part of it might have been that he wanted to prove that he could redeem Gellert Grindlewald. Why else would he leave Grindlewald alive? But mostly I think he wanted to prove that he could redeem himself. I think in his mind he may have felt that he and Grindlewald could rule the world together. Because when you look at his actions it is clear he never changed his views that muggles were inferior beings and needed to be subjugated under wizard rule. The only difference between Grindelwald and Dumbledore is that Dumbledore felt that he could be a benevolent overlord.
In order to prove his theories of redemption Dumbledore had to have someone to redeem. I think he saw the perfect opportunity when he went to visit a young Tom Riddle. His actions with not only Tom but the Matron make absolutely no sense otherwise. In Half-Blood Prince it says that
“Mrs. Cole was an inconveniently sharp woman.”
So Dumbledore hits her with an obvious confundus charm, then proceeds to get her drunk. Things change slightly when Mrs. Cole expresses her misgivings about the boy. Prior to this point I think he was expecting that Tom was a typical wizard child who had the normal accidental magic outbursts and it had confused and frightened the muggles he lived with. But the moment Mrs. Cole tells him some of the things Tom had done his attitude changes.
“..You mean he is a bully?” asked Dumbledore.
“I think he must be,” said Mrs. Cole, frowning slightly, “but it’s very hard to catch him at it. There have been incidents… Nasty things…”
Dumbledore did not press her, though Harry could tell that he was interested. Harry, as portrayed in the books, is not a hyper-observant kid, contrary to what his upbringing would have certainly engendered in him. I think the interest shown by Dumbledore would have had to have been quite pronounced for Harry, as portrayed in the book to have picked up on. I can see Dumbledore looking like a kid at Christmas. I also think that the memory that Dumbledore showed Harry had been sanitized somewhat. Because the description of the orphanage does not match what was typical for the place and time. He could not risk the possibility that Harry might begin to empathize with Tom Riddle any more than he already did. Dumbledore had even asked Harry
…“Could you possibly be feeling sorry for Lord Voldemort?”
Harry, so eager to not disappoint his mentor very quickly quashes that empathy and answers no. I think looking around at the place and seeing how miserable it was and hearing Mrs. Cole’s description of the boy, Dumbledore made up his mind right then that this child would be a perfect subject for his experiment. His actions make no sense otherwise. He terrorizes a very troubled child, he gives Tom even less information than Harry got when introduced to the magical world, and THAT is saying something.
Tom Riddle was an experiment for Dumbledore and he created Voldemort, but ultimately it was an experiment that got out of hand and got away from him. I think that was what he was trying to hide, that he was the cause of the two Voldemort wars. I think he was genuinely trying to stop the wars but only on his terms and by using the exact same means whereby he had created Voldemort in the first place. He tried this experiment three times, he tried it with Tom, he tried it with Severus Snape and he tried it with Harry. Of those, only his experiment with Severus had marginal success, but it showed how flawed the theory actually was. He had partially redeemed a dark wizard, yes but the result was a deeply troubled individual. He tried again with Harry but ultimately that experiment was a failure because Harry did not turn “dark”, to be later redeemed by Dumbledore. I think the argument could be made that Dumbledore was either intentionally trying to turn Harry dark, or he spent sixty years in a school and learned absolutely nothing about human nature, or else he is either ridiculously naïve or a functional idiot.
However, his experiment succeeded in one way in that at least Harry did bring down Voldemort in a way that did not expose Dumbledore’s culpability in creating the mess in the first place. Of course by that time Dumbledore knew his experiments were unmitigated failures and everything was then focused on damage control. End the war and not only preserve but increase his legacy. It’s the same thing that cult leaders do when they know the whole thing is about to implode, they want to insure they will be remembered. Dumbledore wanted to prove that tainted means could produce a pure result, which for all his vaunted wisdom was monumentally ignorant.
Dumbledore was beyond a master manipulator, he was a super narcissist and a sociopath. He shows a distinct lack of empathy. The only thing he seems to show remorse for is his sister’s death, or does he? It seems the only thing he is concerned about is whether or not he actually struck the killing blow. All the while completely ignoring the fact that no matter who fired the spell, ultimately he was the one responsible for the altercation.
Dumbledore has no healthy relationships with anyone, sociopaths often have difficulties forming emotional bonds with people around them. Instead of forming connections with people they exploit them for their own ends through deceit, coercion, manipulation or intimidation. He doesn’t seem to have a connection with anyone as an equal.
Dumbledore shows an extreme comfort level with being dishonest and deceitful. He seems to have no qualms about giving vague half-truths or outright lying to get his own way, or to keep himself out of trouble. He will also embellish or twist the truth when it suits him.
Dumbledore also shows a cruel disregard for other people's feelings. He shows no remorse whatsoever for the way he callously uses everyone around him. Case in point he intentionally sends Harry to live with people he knows will abuse him. He intentionally, with malice aforethought guts every member of Slytherin house when he gives the Cup to Gryffindor.
Like the sociopath many, many times Dumbledore completely ignores his obligations and responsibilities. The safety and security of those placed under his care does not even cross his mind before he brings the Philosopher’s/Sorcerer’s Stone into a school full of children. The head of the British Magical Judicial system allows terrorists to walk free. He even allows one of his own to languish for more than a decade in a morally reprehensible prison without ever asking even one question of the man. He shows time and time again that responsibilities are what the little people have to worry about. Dumbledore reminds me very much of Uncle Andrew in C. S. Lewis’ The Magician’s Nephew.
“No, Digory. Men like me, who possess hidden wisdom, are freed from common rules just as we are cut off from common pleasures. Ours, my boy, is a high and lonely destiny.”
Dumbledore has no problem with making a spur of the moment decision for other people with no thought for the consequences. As evidenced by his insistence that Harry MUST live with the Dursley’s despite what they or the child wants. Also by his callous demand to Severus that he must be the one to kill him.
The combination of irresponsibility and impulsivity cause Dumbledore to engage in criminally risky behavior. He was the master of the wards at Hogwarts, he had to have known that Quirrell was possessed by Voldemort. He is hiding the one thing Voldemort wants in the school. He sets up a labyrinth with obstacles tailor-made for Harry and his friends. He must have known Quirrell was going for the stone and he takes a broom and flies to the Ministry. That would have taken hours, he has a floo connection right in his office. If he didn’t want to take the floo from his office he could have walked or flown off the grounds and taken a floo from Hogsmead or simply apparated. Why does he do this? There is no other reason except that he wanted Harry to face Voldemort.
All through the series Dumbledore showed his willingness to sacrifice anyone for his goals, especially those who were part of his Order of the Phoenix. He has the Order members guarding the prophecy, why? There is absolutely no reason for them to guard it. It’s completely secure, the only ones who can apparently touch the damn thing without getting their brain scrambled are those to whom the prophecy refers. No, the only reason for the Order to be staking it out is to call attention to it, specifically Harry’s attention. Voldemort already knows it’s there so Dumbledore knows that at some point Voldemort is going to lure Harry there. Dumbledore purposely withholds vital information from Harry. He needs Harry’s curiosity to be peaked. He knows that Voldemort is trying to lure the boy into the DOM and he knows that eventually Voldemort will reveal himself. The whole thing was a set up by Dumbledore, I can understand Harry not recognizing it was a set up, but it’s a wonder Voldemort and his minions were also stupid enough to fall for it. We know Voldemort fell for it because the Death Eaters were right there waiting for Harry and Co. to come along and get the prophecy for them.
What about before the students left Hogwarts to go rescue Sirius? Harry told Snape that Voldemort had Sirius. Did Snape hold onto this information out of spite, hoping that Sirius would be killed? Did he hold that information on orders from Dumbledore? Or did he tell Dumbledore and Dumbledore held off sending in any Order members until he was sure the fight would be underway?
It had to have been one or the other, either Snape withheld the information for hours or Dumbledore held off sending the Order for hours.
It had to have been Dumbledore that Snape informed. If Snape had contacted anyone in Grimauld Place or any other Order member they would have immediately taken the floo or apparated to the Ministry and would have gotten there hours before the students even arrived. The reason we know this is because the kids took thestrals and flew from Scotland to London, which would have been a three to four hour flight.
So we know the information was not given to any Order members and we do know that Snape DID give the info to Voldemort. How do we know this? Because at the beginning of the Half-Blood Prince when Bellatrix was questioning Snape’s loyalty, Snape tells her that the Dark Lord was satisfied with the information that he had provided. He admits that the information had led directly to the death of Sirius Black. The only information he could have given that would have that result was that Harry and his friends were on their way to the Ministry.
Again that brings up this point, did Snape then delay informing the Order out of pettiness and a desire to have Sirius die? That is certainly possible, but there is no way he would have done so on his own where he would have certainly been caught. We know that Snape would not have desired Harry’s death because of his vow. Did he delay on orders of Voldemort? No, I don’t think Voldemort would have ordered him to delay. Based on the context and the evidence, I think Snape notified Dumbledore and Voldemort at the same time. Because Voldemort would not have wanted to risk losing his spy in Dumbledore’s organization. He knew the question would certainly have been asked, how did the students get to London? Then Snape would have had to justify a four hour delay in notifying the Order.
The inescapable fact is that either Snape or Dumbledore waited hours before sending help. This also suggests that Dumbledore’s people are either idiots or they are under some kind of spell or potion to keep them from realizing that Dumbledore is playing Russian Roulette with all of their lives and is grooming Harry to be a suicide bomber. At a minimum, Moody should have caught this, you can’t tell me that as paranoid as he is that he would have just ignored a four hour time lapse.
No, the most likely scenario was that Dumbledore was expecting Voldemort to lure Harry to the Department of Mysteries and told Snape that at some point Harry was going to be enticed to the Ministry. He would have told Snape nothing more than that it was vitally important that Snape send him a message letting him know that Harry had gone, the message needn’t have been anything more than “it’s happened” or perhaps a message asking Dumbledore to floo call him. Snape would not have given any detail because he didn’t know who might have been with Dumbledore at the time. I don’t think he would have sent a Patronus either, because from the memory that Snape gives Harry, Dumbledore had obviously not seen Snape’s Patronus in a long time, possibly years. No the most logical conclusion is that Snape had some way to instantly contact both Dumbledore and Voldemort, by either the floo or communication mirrors.
I think it most likely that at least four to four and a half hours after the original message Dumbledore would have told the Order members that he had received a floo call from Snape and that Harry and his friends had gone to the Department of Mysteries. Dumbledore would have then sent the Order members to mount a rescue mission. Because the Order doesn’t even arrive until the fight has moved to the Death chamber.
But even then Dumbledore doesn’t show up until the very end. No, he waits until he knows that there is the highest likelihood of Tom showing up. Thus vindicating him before ministry officials and proving his superiority to Cornelius Fudge.
So why does Dumbledore keep so much information hidden? Some maintain that this is because he is so much older than those around him that he cannot see them as adults. Or that he wants to protect them from the harsh truths or keep them out of danger. But Dumbledore shows he has absolutely no problem with sending his own troops into harm’s way or completely sacrificing them for what appears to be no purpose. Arthur was very nearly sacrificed for no good reason. Had it not been for Harry, Arthur would have died. I think Dumbledore knew Harry would be able to see what was happening and move heaven and earth to save Arthur. It was a calculated risk on Dumbledore’s part, if Harry saved him well and good. If he was unable then it would be one more loss that would harden the boy.
During the first war Benjy Fenwick, The Prewitt twins, Marlene McKinnon and others from the Order of The Phoenix are all murdered. Everyone knows they have a mole in the organization. What does Dumbledore do to ensure security? Nothing; were there things he could have done? Absolutely, they have the youngest Potions Master in a century they could have dosed everyone with veritaserum. They could have had everyone make a vow on their magic, Either Dumbledore or Snape could have Legillimized everyone. Even if Dumbledore didn’t want to find the traitor someone should have done something. You can’t tell me that Dumbledore and Snape are the only Legillimens they have access to. At minimum they should have examined everyone for a dark mark. That is the absolute minimum security effort that they should have initiated.
How about the Prophecy? That entire meeting stinks of a set up. Why was the interview held at the Hogshead? Is that where Dumbledore always held interviews? Of course not. The reason given in the books is because that was where Trelawney was staying and she didn’t want to come up to Hogwarts because it was raining so Dumbledore came to her. Where did that explanation come from? From Dumbledore, of course, he told Harry this ridiculous story, it was so bizarre, I think if Harry had been portrayed accurately he would have been bowled over by the stench of Dumbledore’s BS. So we have nothing but his word for why the interview took place in the Hogs Head. Sorry, but that story doesn’t hold water. We know Dumbledore didn’t normally hold interviews there because he clearly held Tom Riddle’s interview for DADA in his office. How the hell did Snape know that there would be something of value to be overheard? Why was he even there if it wasn’t a set up? For some unknown reason only once in his career as Headmaster Dumbledore decides to interview a candidate at a dodgy pub. No, it was a setup pure and simple. He probably interviewed Trelawney weeks or months earlier and she either gave the prophecy then and he bespelled her to regurgitate it on command. Or the prophecy was something he concocted himself and registered it with the Ministry.
Remember Voldemort was winning at the time and if he won Dumbledore may not have survived the fallout. Dumbledore’s experiment would have been a catastrophic failure and his culpability may have been exposed. He certainly would not have been able to stay at Hogwarts. I think in desperation he created the prophecy and was looking for a patsy or two to help him set it in motion. The first dupe was Trelawney, all it would have taken is a quick spell and she would have been able to do whatever he needed. But he needed to have this information fed to Voldemort, that’s the whole reason I think for the interview in the Hogs Head. I think he went further and I think he probably scheduled Snape’s interview for either the same time or very shortly thereafter.
I don’t think Snape overhearing the prophecy was a chance thing. I think it would have been way too important to rely on sheer chance, it’s possible that Snape was also bespelled. Either way I don’t think the meeting played out the way Dumbledore said it did. I would have liked to have seen Harry as he should have been portrayed in the books call Dumbledore out on his BS.
British Wizarding society is shown to be nothing more than Dumbledore’s personal playground and Harry’s whole life was nothing but a set up by Dumbledore. Almost everything Harry suffered could very easily have been as a result of Dumbledore’s manipulations.
Dumbledore abandoned Harry with people he knew would abuse and neglect him. He counted on it. People who think of Dumbledore as a kind and well-meaning grandfather figure are so quick to point out that Dumbledore made the best decision he could and his only concern was Harry’s welfare and happiness. They claim that Dumbledore wanted Harry to have a normal childhood before he would have to fulfill his destiny as the savior of the wizarding world. That line of thinking is nothing more than the propaganda that came from Dumbledore himself. It is an outright lie. How do we know this? Because Dumbledore comes out and admits it to Harry.
“…you had suffered. I knew you would when I left you on your aunt and uncle’s doorstep. I knew I was condemning you to ten dark and difficult years.”
Later at the Dursley's he goes further and confesses to knowing exactly how they treated Harry the whole time.
“...he has known nothing but neglect and often cruelty at your hands.” And “…however miserable he has been here, however unwelcome, however badly treated, you have at least, grudgingly, allowed him houseroom."
Dumbledore claimed that it was done only to keep Harry safe.
“My answer is that my priority was to keep you alive. ..."
Once again Dumbledore was telling only half the truth. His priority was to keep Harry alive but only so that Harry could die at the right moment. How do we know that? Because he confessed it to Snape and we see that confession in the memories Snape gives to Harry. We also see in this memory that Dumbledore was the one who set up or manipulated Harry into the various tests throughout his school years.
“We have protected him because it has been essential to teach him, to raise him, to let him try his strength,” said Dumbledore, his eyes still tight shut. “Meanwhile, the connection between them grows ever stronger, a parasitic growth: Sometimes I have thought he suspects it himself. If I know him, he will have arranged matters so that when he does set out to meet his death, it will truly mean the end of Voldemort.”
He deliberately tells Severus a half-truth here. Harry doesn’t “arrange matters” Dumbledore does. Harry is just a child soldier how is jumping through the hoops Dumbledore has set for him. He doesn’t tell Snape that he has tasked Harry with finding and destroying Horcruxes. Because there is no way in hell that if Snape knew what the mission was he would leave it to Harry and his friends. As far as Snape is concerned Potter is barely functional. He would have gone Horcrux hunting either with or without the kids but he would not have left it to them.
Dumbledore opened his eyes. Snape looked horrified. “You have kept him alive so that he can die at the right moment?”
In the next breath Dumbledore mocks Snape’s shock at his callousness.
“Don’t be shocked, Severus. How many men and women have you watched die?”
“Lately, only those whom I could not save,” said Snape. He stood up. “You have used me.”
“I have spied for you and lied for you, put myself in mortal danger for you. Everything was supposed to be to keep Lily Potter’s son safe. Now you tell me you have been raising him like a pig for slaughter —”
“But this is touching, Severus,” said Dumbledore seriously. “Have you grown to care for the boy, after all?”
This scene illustrates exactly why Dumbledore keeps information from everyone, especially from his own followers. If he had told Snape his plans right after Lily was killed Snape would never have sold himself to Dumbledore.
Dumbledore keeps information from people and outright lies to them because he knows that they would not trust him if they knew what his plans were. He knows that no one would follow him if they knew. He knows that they would not do what he wanted them to do if they knew his plans. Fundamentally, Dumbledore knows that he is not to be trusted. That his plans and desires are not in people’s best interests so he must lie, obfuscate, and manipulate to get them to do what he wants. He must keep them blinded by his persona and enslaved to his cult so that they have no choice but to yield to his demands.