Are people seriously still mad that the equalist are portrayed as morally wrong? Why is that bad writing? They’re evil, they’re wrong, they’re dirty hypocrits, they didn’t have a good reason for what they do. Why does a villain have to be grey? Some of the best villians can be completely black, like Voldemort, the Joker or the Daleks. Hell, exactly what redeeming qualities did Ozai and Zhao have? C’mon people.
Ozai and Zhao didn’t represent the entire Fire Nation at the end of the day. Fans were impressed when AtLA didn’t demonize and categorize the entire Fire Nation as all villains. AtLA actually showed that not everyone in the Fire Nation was like Ozai and Zhao—see Zuko, Iroh, kids at one of the Fire Nation academies, Piandao, Fire Nation commoners, etc. The Fire Nation was varied, it wasn’t dominated by any one moral range. EVEN THOUGH THE FIRE NATION HAD A CONCRETE HISTORY OF GENOCIDE AGAINST THE AIR NOMADS AND STARTING A WAR. The Fire Nation historically committed horrible crimes, and yet they still received depth, the acknowledgment that the Fire Nation is not wholly evil, that it is varied, that they were human. AtLA treated every character as human. That resonated with fans, as that reflected the world—groups of people, just people, are not generalized as wholly evil or wholly good. That reflection of the world grounded AtLA in a greater realistic tone, despite the high fantasy setting.
I’m pretty sure people rather expected the spin-off sequel to AtLA to continue treating every character as human, to continue that realistic tone of not generalizing people. Instead all the Equalists are generalized as being only morally wrong, while the Fire Nation had been allowed to be varied, and was not generalized. Even though the Fire Nation had a history of genocide, WHILE THE EQUALISTS DID NOT. In comparison to the Fire Nation, the Equalists still come off as more tame—they chibock people, not burn them; removing bending was fine for Aang, it was the merciful option over execution, why is it so bad for the Equalists to have bending removed, it’s better than simply killing benders? (Bending removal is another topic entirely—but I will say that actually killing and actual genocide with people actually dying is still far worse than losing bending.) Whatever canon intended, there are still too many hints that nonbenders, the ones Equalists are trying to fight for, are mistreated. And yet despite this, despite being less violent than the Fire Nation, less damaging, the Equalists are reduced to being just morally wrong. While we got to see so many faces of the Fire Nation and taste their perspectives, we saw barely a handful of the Equalists and had little idea of their experiences.
So yeah, people will dislike that after the genocidal Fire Nation got depth and weren’t reduced to only being morally wrong and actually had multiple voices and were shown to be human, the chiblocking and non-genocidal Equalists with general grievances are all labeled as morally wrong and are never given a variety of voices and never seen as really human. It’s just this very weird dissonance between AtLA and LoK, this downgrade in who gets to be viewed as human. It’s frustrating.
And did you actually forget about Azula? Of course, she rather disproves your point about black hat villains v. grey villains, at least with regards to Ozai and Zhao, her ending up as a grey villain and ending up a stronger character/villain than Ozai and Zhao. It seems common for people to criticize Ozai as being too flat, and Zhao may be slightly liked more than Ozai, but he didn’t necessarily have Azula’s staying power, though he did get an intriguing death scene where he refused to be saved by Zuko, so probably some grey there where Zhao actually stuck to his guns.) Still, I think it’s safe to say that in Avatarverse, Azula outstrips them in popularity with the audience, and I think that could be attributed to her having some depth, or “grey.” In Avatarverse, it seems like the grey villains are more often the better ones.
Also, Joker is a good example of an outright black hat villain, but I wouldn’t say Ozai and Zhao really compare to him. Though admittedly, I think some of Joker’s appeal are other things added to his black hat status, like his humor, occasionally philosophical bent tending toward the most cynical view of the world, and complex relationship with Batman. I don’t think Ozai and Zhao have something comparable, and that plays into them rather enduring less than the Joker.
I cannot comment on the Daleks as I know nothing about them.
I doubt Voldemort succeeds as a compelling black hat villain, as I’ve gathered that people find him ultimately too flat. Like a character can be so good, they’re boring, a character can be so evil, they’re boring. Such extremes on either moral scale can be boring, though there are exceptions (i.e. the Joker, but again, I’d argue the other nuances to him round him out into someone more compelling.) Mixes of good and evil within characters are typically more interesting—it’s that contrast that fascinates people.
And so, people are probably annoyed that the Equalists aren’t allowed to have complexity—there’s little contrast within them, no grey when they’re reduced to being just black hats.
Also, I’m just gratified that apparently a lot of people are still irritated over the Equalists being portrayed as so utterly morally wrong—rock on reasonable disappointment in poor writing, rock on.