The first indication we get that the Dursleys, far from simply not wanting to expend any time and effort on his behalf, are going out of their way to make Harry as miserable as possible is seen in Chapter 3 of PS.
There was a horrible smell in the kitchen the next morning when Harry went in for breakfast. It seemed to be coming from a large metal tub in the sink. He went to have a look. The tub was full of what looked like dirty rags swimming in gray water.
“What’s this?” he asked Aunt Petunia. Her lips tightened as they always did if he dared to ask a question.
“Your new school uniform,” she said.
Harry looked in the bowl again.
“Oh,” he said, “I didn’t realize it had to be so wet.”
“Don’t be stupid,” snapped Aunt Petunia. “I’m dyeing some of Dudley’s old things gray for you. It’ll look just like everyone else’s when I’ve finished.”
Harry seriously doubted this, but thought it best not to argue. He sat down at the table and tried not to think about how he was going to look on his first day at Stonewall High—like he was wearing bits of old elephant skin, probably.
So Petunia is dyeing some of Dudley’s old clothes for Harry to wear to school.
At first, this doesn’t seem like much—the Dursleys already dress Harry only in clothes that won’t fit Dudley’s massive bulk any longer, so doing this sort of thing rather than buying Harry his own uniform is par for the course—but if you spend some time really thinking about it, it’s positively insidious.
Let’s take a look at the facts from what we see in the canon.
The school, Stonewall High, is (in British terms) a comprehensive or state school—because Smeltings (a public school in British terms, meaning that anyone can enroll so long as they can pay the tuition fees) is too good for Harry, by the Dursleys’ reckoning, despite the fact that Vernon could almost certainly afford the tuition for both boys—that apparently has a uniform policy. Petunia claims that the rags she’s boiling will “look just like everyone else’s when [she’s] finished”, but this is dubious at best.
Consider this. Surely a school with uniform requirements like Stonewall High would have a lost-and-found; there’s almost certainly no shortage of lost, misplaced, or outgrown uniform pieces that have gone unclaimed over the years (hey, kids lose stuff, and outgrow it—it’s a fact of life). How much time and/or effort would it take for Petunia to go down there one day (surely her antiseptic house can wait a few hours) and pick up a few stray, unclaimed items close enough to Harry’s size to get by? If nothing else, maybe a few students would be willing to donate items they’d grown out of for the sake of kids who couldn’t afford their own—hell, the school probably gets donations for such a purpose already. After all, kids grow out of clothes pretty quickly, and the old stuff would just be taking up space.
Dressed in gently-used clothes (probably far more gently-used than anything Dudley had previously worn, and thus probably in better condition than any clothes Harry could remember wearing), Harry wouldn’t look perfect (even next to Dudley's uniform—who designed that monstrosity?), but at least he’d look decent—and it would have the side benefit (as far as the Dursleys’ apparent view that getting Harry a uniform would cost too much is concerned) of costing them very little, if anything. And it wouldn’t be too much trouble to keep it up—returning items as Harry outgrew them in exchange for more gently-used but better-fitting items. Hell, considering how fast kids grow, it might be a better solution anyway, especially if they got items designed for Harry to grow into before he grew out of them. The Dursleys save a bundle and no one asks any questions. Everybody wins.
But that’s the drawback, as far as the Dursleys are concerned—everybody winning includes Harry. You see, there would be a chance of Harry being happy.
Consider this. Had those Hogwarts letters never come—as the Dursleys clearly hoped they wouldn’t—come the end of summer, Harry and Dudley would be going to different schools for the first time in their lives. This would also mean separating Harry from his cousin and his cousin’s gang, as it’s implied that said gang would all be attending Smeltings (the other boys may very well be children of some of Vernon’s old schoolmates). Dudley and his gang are noted in the narrative as not only beating Harry up on a regular basis (“Harry Hunting” is described as a “favorite hobby” in PS, and it’s implied in OP that Dudley’s gang prefers targets that can’t fight back), but deliberately keeping any potential friends away from Harry all through primary school (“At school, Harry had no one. Everybody knew that Dudley’s gang hated that odd Harry Potter in his baggy old clothes and broken glasses, and nobody liked to disagree with Dudley’s gang.”). Thus, Harry might even be able to make friends at Stonewall. Also, even if his teachers believed the Dursleys’ blatant lies about him being a delinquent, Harry’s refusal to let his relatives’ words become self-fulfilling prophecy would prove them wrong. From all appearances, Harry would get a decent education, and a chance to be a normal kid rather than a pariah, proving that the Dursleys are flat-out lying about him. And he’d probably have a good shot at getting into a good university—and, eventually, out of the Dursleys’ lives for good. In short, again, he could be happy.
Can't have that, now can we?
So instead Petunia is willing to buy clothing dye, and spend time and energy (not to mention stinking and likely dirtying up her perfect kitchen) to make sure that Harry will look nothing short of ridiculous on the first day of school; to make sure he will be targeted by every bully there, that he will be an outcast—and thus miserable—from minute one. Harry would not have the opportunity to try to make a first impression—it would be made for him, and it would not matter if he was separated from Dudley; he’d attract a whole new set of bullies to pick up where his cousin left off. Flat-out evidence that Harry was effectively without parental protection (a kid’s physical state when he comes to school says a good deal more about the parents than the child himself) would be like blood in the water. A child who is clearly ill-cared for indicates to bullies that he is effectively without parental protection, and thus an open target.
It’s really despicable that she takes it this far. The fact that she’s willing to go to the expense of dyeing Dudley’s old clothes when there are other obvious—and even less expensive or time-consuming—solutions to the problem (as I have pointed out) tells me that she’s just plain picking on Harry. Not to mention her apparent willingness—eagerness, even—to sabotage his education (and thus his future) just so she can get some sort of petty revenge on her long-dead sister. Just because Lily got to be magical and Petunia didn’t.
Also, for someone endlessly concerned with what the neighbors think, Petunia is begging to be gossiped about herself. Surely there’s been word passed around about Harry’s appearance already—and I’d be surprised if Dudley’s bullying wasn’t at least occasionally mentioned, even if Vernon and Petunia refuse to hear it (“He’s a boisterous little boy, but he wouldn’t hurt a fly!” as Petunia, in clear denial, says in GF).
All things considered, Petunia should be grateful for those letters showing up, because once Harry began at Stonewall, it would have gotten worse in a hurry.
Consider this. Once word got out that Harry Potter was coming to school in Dudley’s old clothes dyed gray because his relatives refused to procure him a proper uniform (even if not a brand-new one), Petunia would come under a great deal of scrutiny. Due to the scenario described above, she wouldn’t have the excuse of being unable to afford new school clothes for Harry—the solution I have described would require minimal time, effort, and money (and probably a lot of other parents did something similar anyway). The truth would come out. It would be pointed out that she was able to afford tuition fees and all new clothes for Dudley—and before he lost all that weight, she probably needed to take him to a specialty store or hire a tailor! Also, surely the number and caliber of Dudley’s birthday (and, presumably, Christmas) presents, as I have noted above, was well-known around the neighborhood (again, if Dudley’s anything like his parents, he probably rubbed it in the other kids’ faces every chance he got, to the consternation of said kids’ parents)! Even claiming—as Petunia likely had ever since Harry started school—that Harry would only wear Dudley's castoffs wouldn't hold up under close scrutiny unless Social Services was run by total morons—and besides, he wouldn’t be allowed to wear street clothes at Stonewall! Also, if Harry was “incurably criminal” as his relatives insisted, what was he doing at a regular primary school in the first place, and why was he set up to attend a comprehensive secondary school? Any teacher worth their salt would have at least wondered.
This brings a lot of things into question—what kind of stuff happened on Privet Drive between the first and second chapters of PS? Had Petunia taken Social Services never showing up for granted? If so, she was seriously pressing her luck! Maybe she really did hope they’d take Harry away from her—but then the only problem with that interpretation is that they likely would have taken Dudley away as well, and she’d have to be an idiot not to figure that out. (There is, however, the possibility that she would have been happy to have them both out of her life—considering Dudley, who could blame her?—but that’s going into Wild Mass Guessing territory.)
And the really sad part is that Harry—who is bright enough to put all the pieces together—realizes that he’s going to be a pariah even at Stonewall thanks to his aunt, and it never occurs to him to argue, or to try and do something about this.
Then again, who has he got to go to?
Another thing deals with how they finally deal with explaining Harry spending nearly ten months out of the year away. It would be a simple matter to explain that Harry had some kind of legacy scholarship or trust fund set up for him to attend his parents’ old school. It would be easy enough to explain that the Potters had even written it into their will. Everything would be taken care of. This would have the side benefit of explaining anything odd about Harry’s appearance or mannerisms (certain old boarding schools, from what I’ve heard, have odd traditions) and explain why he’s neither at Stonewall nor attending school with Dudley.
But, again, such an explanation would forgo humiliating Harry and wouldn’t fit the Dursley narrative of Harry being a hopeless case (and thus scare away anyone in the neighborhood who might otherwise associate with him). To the Dursleys, Harry is eternally a “freak” and must be treated accordingly, so they make up an institution for hopeless cases. This also lets them justify keeping Harry locked up in his room during the summer months, cutting off his contact with the outside world, putting bars on his windows and not any other window in the house, and so on. As far as the neighborhood is concerned, the Dursleys have taken in their incurably criminal nephew out of the goodness of their hearts. It makes the Dursleys look good.
The Dursleys seem to delight in Harry’s misery. They laugh at him when Marge’s dog chases him up a tree. They lock him in his room, have bars bolted to his window, and shove cold soup under the door in CS, building a cat-flap into his door so they don’t even have to open it long enough to interact with him. Vernon even seems to take sadistic glee in hurting Harry whenever he can—whether we’re talking about keeping Harry from reading any of his Hogwarts letters in PS (tearing them to shreds in front of Harry and even wishing aloud that he had some of them to burn on the house on the rock—again, in front of Harry), locking him up in his room in CS (while forcing him to pretend he doesn’t exist, on his birthday), or forcing Harry to lie about where he spends the school year (again, at an institution for “hopeless cases”) and listen quietly while Marge slanders both him and his parents left and right (again, whenever he’s in earshot—clearly she’s hoping for a reaction) in PA. It’s only when Harry brings out the threat of his supposedly murderous godfather—who was considered a large enough threat for the Ministry to get the Muggle population involved in finding him… and who I imagine Harry took great pains to paint as being very protective of him—that Vernon lets Harry go to the World Cup. From then on, every time Harry leaves the Dursley house, it’s with some kind of escort (and each time the level of protection is escalated—the Weasleys in GF, the Advance Guard in OP, Dumbledore himself in HBP, and a group of Order members and Harry’s friends in DH). The only thing that motivates the Dursleys to treat Harry like a human being is the knowledge that people who care about Harry are watching them and are likely to take exception to that fact. Also, Harry soon gains the ability to defend himself if he needs to—and it’s no fun hurting someone who can hurt you back, is it?
Vernon may not beat the crap out of Harry as he does in dozens of fanfics—though he shows signs of being potentially physically abusive (he even hits Dudley in PS—“[Vernon] had hit him around the head for holding them up while he tried to pack his television, VCR, and computer in his sports bag”—showing that he could potentially become physically abusive)—but what he does in canon is bad enough. And I’m not just talking about his strangling Harry in OP either.
Harry seems to function as a punching bag for Dudley and Dudley’s friends—at least until Harry’s able to dodge or fight back (at the very least, Harry can thank Dudley for helping him develop those Seeker reflexes; and he’s also pretty quick with snide comebacks when he needs to be, despite the fact that they tend to go right over Dudley’s head).
It gets worse. While the Dursleys do not actively encourage their son’s misdeeds, they damn sure don’t discourage them—and in my experience, that’s essentially the same thing. Kids probably learn more from their parents’ example than they ever do from their words, and the Dursleys teach Dudley by example that some people deserve to be treated well, while others deserve to be treated badly simply by virtue of who they are (not unlike the rules Draco Malfoy and the other pureblood fanatics seem to have grown up with). When kids are involved, I’ve noticed that actions definitely speak louder than words.
For most of Dudley’s life, he’s been taught that the usual rules don’t always apply—or at least not to him. This causes problems, because in a just society, the rules either apply to everyone or they basically don’t apply at all—ergo, if the rules about bullying only apply in certain situations and to certain people, what about the other rules? If “don’t beat people up” doesn’t apply to him, what about “don’t steal from other people”? Or “don’t murder other people”? This is the kind of mindset that creates career criminals. Hell, the Dursleys were unwilling—or unable—to see that Dudley was turning into an out-and-out thug.
Dudley seems to see nothing wrong with picking on Harry in plain sight—and, as noted in OP, beating up defenseless ten-year-old kids with the help of his gang without fear of reprisal—clearly taking his parents’ protection from any consequences for granted. As I’ve mentioned before, Dudley seems to enjoy depriving Harry as much as his parents do—pre-Hogwarts, Harry couldn’t even have a moment’s peace at school, and Dudley’s gang kept any potential friends from approaching Harry.
Let’s face it—Dudley was headed for a very bad end before the dementor, and every time his parents caved to his demands was another nail in his coffin.
The Dursleys adore their son—there’s no denying that—but they seem to confuse giving a child what he wants with giving a child what he needs. As any parent worth his salt will tell you, that’s a very important distinction. Encouragement and criticism—the carrot and the stick, as they used to say—play an important role in a child’s development. A child who never hears praise or encouragement is obviously disadvantaged compared to a child whose genuine achievements, however small, are pointed out and respected.
Which one is more likely to be bold, to try things, and to improve?
Conversely, a child who is never criticized is likely to become… well, to become someone not unlike Dudley.
The Dursleys could be said to be an indictment of the “self-esteem movement” of the past few decades—those who have insisted that children should receive lavish doses of praise regardless of their performance. Those who have high opinions of themselves may say they are very successful in their job and their social lives, but that’s subjective—people who have high opinions about themselves… have high opinions about themselves. Are they really successful by some outside standard just because they have self-esteem?
There is no statistically significant connection between high self-esteem and genuine achievement, ability, or successfulness. Not in the real world. High self-esteem isn’t proof that you’re good at something any more than low self-esteem is proof that you’re bad at something. Hell, artificially boosting self-esteem may actually lower subsequent academic performance.
The Dursleys come down on Harry like the proverbial ton of bricks if he so much as thinks something they don’t like, while Dudley—a certifiable thug by OP—gets carte blanche. Good parents manage to find a balance between them. It doesn’t help that the Dursleys seem incapable of understanding what’s good for their child, or believing that Dudley could do any wrong simply by virtue of being their child. They taught him that he never had to take responsibility for his own actions.
Now that I think about it, they are pretty much the exact inverse of the Weasleys—who cannot imagine not loving a child under their care, and are always happy to set an extra plate at the table. The Dursleys grudgingly took Harry into their home with loads of conditions; the Weasleys happily took Harry into their home (and their hearts) with no conditions whatsoever. He was Ron’s friend, and that was enough. The Dursleys are endlessly concerned with appearances yet cannot see their child as capable of wrongdoing even when it’s blatantly obvious; the Weasleys are very close-knit and concerned not with appearances but with loyalty and love (and Molly, at least, is very concerned about what her children get up to and is more than willing to offer criticism when it’s deserved). The Dursleys live in a decent-looking home that is nonetheless emotionally sterile; the Weasleys live in a ramshackle old house that is filled top to bottom with love, kindness, and affection. The Dursleys hide who they are from everyone; the Weasleys wear their hearts on their sleeves and don’t care who doesn’t like it. Small wonder Harry likes the Weasleys so much.
As noted above, the Dursleys were harming Dudley as much as or more than Harry—Dumbledore even calls them on it in HBP, as seen in the quote above, implying they were harming him to a far worse degree than Harry. Dudley doesn’t seem to get it at first—and the very idea of mistreating Dudley leaves Vernon gobsmacked… though you could argue that Petunia sort of gets it, from her reaction…
If they’d taught Dudley the connection between work and achievement—in other words, if they’d had so much as a micron of common sense in raising him—he’d have been better off.
Harry came out remarkably well-adjusted (but not unscathed), while Dudley was an entitlement baby—on his way to being completely unprepared for life in the real world, and likely to be an outcast for the rest of his life, considering that his more antisocial tendencies were never discouraged. And if something had happened to Dudley as a result of the universe trying to teach him those hard lessons, Vernon and Petunia would have done what they’ve always done, and blame society or something.
If not for that dementor, Harry would still have become a hero, but Dudley might very well have remained an out-and-out thug.
Dudley basically had no concept of the word “no” applying to him during quite a bit of his childhood and early teens. He is damn near worshiped by his parents, and has been raised to expect everything to be handed to him without question and to bully others into giving him what he wants.
Granted, the Dursleys finally start trying to be decent parents eventually—the diet in GF comes to mind, but that’s only because people are starting to talk. And it doesn’t help that they eventually get Dudley to agree to it by ensuring Harry always gets even less than he does.
The danger with raising a child along these lines is that someday the world may teach him in a very profound and life-altering way that the word “no” does indeed apply to him just as much as everyone else.
And in Dudley’s case, it did. He nearly got his soul sucked out in the process, too.
It’s interesting that Dudley was rescued by people he’d always dismissed as worthless—Harry and Mrs. Figg. It finally forced him to get a move on toward getting his priorities straight.
According to JKR, “[w]hen Dudley was attacked by the Dementors he saw himself, for the first time, as he really was.” Dudley clearly did not like the picture thus presented. You could say this is a device JKR likes to use—characters encountering versions of what they might become, and rejecting them.
Harry rejects the idea of becoming like Voldemort or even the Dursleys themselves (or, you could argue, like Snape, as Harry learns to let go of his prejudices rather than holding on to them like Snape does).
Hermione rejects the idea of refusing to accept criticism and thus becoming like Umbridge.
Ron rejects the idea of giving in to his insecurities and becoming like Draco Malfoy.
Sirius rejects his family’s ideals, and Regulus ultimately rejects Voldemort for the sake of his house-elf.
Lupin rejects the urge to become like Fenrir Greyback.
And Dudley, bless him, rejects the idea of becoming his father… or his mother, for that matter. If nothing else, it earns him Harry’s respect, and the two men—according to JKR—keep in contact in future years.
And so Harry and Dudley show signs that they’re going to be okay despite their upbringing… though, granted, I’d suggest both of them go about finding decent therapists.
The Dursleys are, simply, lousy parents, and not very good at love. They’re mentally screwed-up and emotionally stunted. They know damn well how badly they’re treating Harry, and as long as they can convince themselves that Harry should consider himself lucky to have that much, they’re just fine with it. It helps that they can paint themselves as suffering saints who took in a child—and said child as hopelessly damaged (through no fault of theirs, of course), with no chance of making something of himself. It doesn’t matter that they don’t even try to be decent parents so long as no one knows. They’d rather tell people Harry spends all but a few weeks out of the year at a frakking institution for hopeless cases (the kind of place where just being sent there would tell you that everybody’s given up on you and thus become a self-fulfilling prophecy) than come up with a story that wouldn’t paint Harry as awful and terrible and themselves as oh-such-good-people for taking him in and putting up with him (oh, and scare any potential friends or allies away from Harry, of course).
And possibly the worst thing about all this is that Dumbledore has to have known about what Harry went through. The problem is that, by all indications, he literally could not act, knowing that not only were the Dursleys the only people with legal standing to take him in, the protection of Lily Potter’s sacrifice was too important to lose, even if the price was a loveless childhood for Harry. Maybe there was interference to keep Social Services from meddling, who knows? I can see Dumbledore beating himself up over it (it’s not like he lacked for that sort of thing—God only knows he seems to have beaten himself up over Ariana), but that’s me.
Either way, when Dumbledore finally called the Dursleys on their treatment of Harry, part of me cheered, since I’d been waiting five books for it. We later find out that this was partly Dumbledore getting his affairs in order—he knew from Snape that he had a year left thanks to the curse on the Ring Horcrux—but it’s good to see that Dumbledore knew he’d screwed up and was willing to call the Dursleys on their crap. It probably helped Harry’s perception of him as well.
The fact that Harry was left with the Dursleys in the first place—never mind that he forces Harry to go back to them each summer—has also affected fandom perception of Dumbledore (or, at the very least, it gives those who already don’t like him an excuse to attack him). I would argue that Dumbledore is a flawed individual—a good man trying to do the best he can with the options he has available to him… and also a man who too often does not allow himself to see anything but the best in people (which is probably among the few reasons Snape is kept on as a teacher, but that’s another essay). He seems to have believed that Petunia could get past her hatred of magic (which was likely exacerbated by Vernon’s presence).
Also, for all we know, nobody ever came forward to take care of Harry. Harry’s grandparents on both sides were dead, Remus (due to his self-confidence being completely and utterly shot) believed himself incapable, Sirius was in prison (and his guilt over the whole affair kept him from even trying to escape for more than a decade). Peter was believed dead (though, as we know, he was the traitor that betrayed the Potters… and was living as Percy and later Ron Weasley’s pet), and if there are any others who could have taken him in, they’ve never been mentioned. He may have had a godmother, but she might have died in the time between his birth and Voldemort’s visit to Godric’s Hollow. People may even have hesitated to take him in after what happened to the Longbottoms.
If we take the blood-protection story at face value, there really was some special sort of magic that protected Harry through his early childhood. Said magic may also have shielded him from the worst psychological effects of his relatives’ treatment, but that too is another essay.
Since it’s my policy to be as fair as possible, I have to acknowledge that Harry did learn some valuable, if harsh, life lessons from the Dursleys—he learned to look out for himself (if nothing else, he's self-sufficient—I can see him and Ginny sharing the household chores), to think for himself (he chose to be “Dumbledore’s man, through and through” of his own free will, even after finding out about the skeletons in Dumbledore’s closet), and to be wary of immediate inclusion. And thanks to the Dursleys, Harry hates bullies, knowing full well what it’s like to be on the receiving end. Remember his reaction to Snape's Worst Memory, folks—finding out his father was a bully rather than the role-model Harry had long believed him to be causes him to have a near-breakdown.
If he hadn’t learned those lessons, he’d probably have befriended Draco Malfoy instead of Ron Weasley—like so much of the Misaimed Fandom seems to wish he had (note to fangirls, Ferret-Boy is neither Tom Felton nor a “cool kid”, but a bigoted little twit who never had a thought that wasn’t originally Lucius Malfoy’s in his life)—and been drawn toward the Dark.
This can’t be overstated.
Harry learned from the Dursleys that being prosperous does not make you a better person by default; that being wealthy does not necessarily equal being more valuable than someone else—a lesson that would have served Draco Malfoy (and his horde of fangirls) well. Harry is embarrassed by his fame and his riches—neither of which have anything to do with him personally but rather his parents—and never judges the Weasleys for their lack of money, even if he probably still longs to find a way to slip them some of his own. I like to imagine Arthur and Molly getting high-quality (and practical) gifts on their birthdays, anniversary, and Christmas from him and Ginny (probably the same for Ron and Hermione).
Yes, it could easily be argued that without the Dursleys, Harry might have turned out to be a very different person. Though who’s to say that he wouldn’t have learned those same lessons from living with a loving family (the Weasleys, for example)?
But, of course, nature vs. nurture is only two thirds of the argument. I tend to think that choice had a role here—as mentioned earlier, I think that at some point Harry made a conscious choice not to let the Dursleys’ slandering him as a hopeless case become a self-fulfilling prophecy—if Tom Riddle had made a similar choice, the Potterverse would be a better place.
Harry is eventually able to stand up to the Dursleys, which shows how much he’s gone through and the effect it’s had on him. I can imagine it’s quite therapeutic to call your abusers on how utterly full of crap they are, knowing they can’t do a damn thing about it (bullies are, by definition, cowards—what other sort of person only attacks people he knows can’t or won’t fight back?).
As I say, the Potterverse may not be the best of all possible worlds, but it could have been a whole lot worse.
One wonders what it would have meant for the wizarding world if the Dursleys actually had dropped Harry off at an orphanage…