Zuko is essentially the fangirl wet dream of Avatar. Full of angst, dark and troubled past, handsome but slightly imperfect, huge woobie, badass, atoner who joins the good side, and in the eyes of many extremely shippable. His fanbase is HUGE, and it's not even just about ZOMG HOT ANGSTY GUY either. People love to laugh at his utter dorkiness and be blown away by his awesome character development. Hell, I'm one of them! I usually never go for angsty bad boys the fandom creams themselves over, but Zuko just amazed me.
But like most characters, Zuko is not without his detractors. To be fair, a good number of these people are understandably bitter fans who find he's been overrated and over-glorified to the point where people trivialize what any other character on the show goes through or any of their achievements or good points. This I understand, as much as I love Zuko I do hate how people focus on him to the exclusion of everyone else.
And then there are people who just flat-out bash him for stupid reasons. Aang may be the most bashed male character on the show, but Zuko's gotten some pretty harsh hate thrown his way, too.
1. "He's such a whiny mama's boy!"
Cause God forbid a guy love his mother with all his heart and not be made of steel, right? Zuko was very attached to his mother, it's said that aside from Iroh she was the only member of the family who really cared about him. Ursa was a devoted and loving mother, and she probably doted on both her children. But Azula started rejecting it and clinging to Ozai as she got older, so Ursa focused her attention on Zuko, who appreciated it.
When Ursa went away, of course the guy was gonna be devastated. He misses her, and the last words he says to Ozai in the finale are a demand to know where she is. But this doesn't mean he's weak and pathetic and constantly pining away for his mommy. Nor does it mean that as a child he was a pitiful little waif who needed her to survive. He did have Iroh, and Lu Ten (for a while), and it's implied that he and Mai were pretty close friends.
2. "He was a stupid crybaby about the war meeting, he insulted his father and he totally deserved that scar! I mean, come on, when you piss off daddy you totally deserve to have your ass spanked!"
First of all, when he complained to Iroh he had a point: As heir to the throne, he had the right to know all this important war stuff.
Second...yeah, it's stated that he WAS wrong for speaking out of turn, but his heart was in the right place. But really, even if he'd put his protest more maturely and been adult about it Ozai still would've been pissed off.
Third, he did not "get his ass spanked", Ozai shot him with a goddamned fireball and nearly burned half his fucking face off. That's not a standard punishment for disobeying Daddy, that's just cruelty. Yes, I know, different culture and different values, but it should be clear by the lack of men with huge glaring facial scars like Zuko's that even the hardest to please of Fire Nation fathers don't do this sort of thing. :P
So in essence, Zuko was wrong but that doesn't mean he deserved to be publicly scarred and humiliated.
3. "It's all Zuko's fault everyone hates Kataang! Down with Zutara, and down with Zuko!"
*siiiigh* This is just silly. Fine, so Zutara is probably the most popular Avatar ship. Big whoop! It doesn't mean jack shit other than that a lot of Avatar fans online happen to like Zutara, so let it go. Shipping is not a contest. Just like one pairing isn't better than another by virtue of being canon, one pairing is not better than another by virtue of being OMG POPULAR!! And yes, enough Zutara fans are obnoxious enough to ruin the ship for other people.
Neither of these are Zuko's fault. If you're looking for something to blame, blame the general attitude in fandom that shipping is all about sex and popularity.
4. "LOL Zuko's such an emo loser, that's funny! Let's pretend he's got nothing else to his character and forever paint him as a whiny emo loser mommy's boy who's obsessed with honor and can't take two steps without falling over and getting raped in the butt!"
*eyeroll* Oh, fandom, why do you hate character development and looking beyond the surface so much? I don't even think Zuko counts as actually being "emo". He's just often cranky and introspective and takes a while to get his head on straight. That's not being emo, that's being stubborn and 16 years old.
5. "He doesn't care about anyone but himself!"
I guess I can't argue there, 90% of the time he's obsessed with catching the Avatar, making Ozai love him, and his honor. But even in season 1 he has his moments where he realizes that's not all there is to life. Remember how he passed up chasing Aang in order to rescue Iroh in "The Spirit World" part 1? Or in "The Storm" when he made up for being a jerk earlier by making sure the crew was safe during the worst part of the storm? Or even tried to save Zhao from an angry Ocean Spirit despite the fact that Zhao tried to have him blown up two episodes earlier?
So there you have it. Zuko's not perfect and sometimes you wanna smack him, but he's not a whiny loser or a pathetic idiot who deserved to have his face burned. He starts the series as a short-sighted, selfish antagonist and by the end he's a man who understands the true meaning of honor and the value of caring about others.