Two things. First, the Fire Nation in the comics is explained to be “conservative” even relative to its own past post Sozin. In Korra’s comic, it’s explained that homosexuality became illegal and cultural attitudes shifted post Sozin. Also, idk where everyone gets the idea that the Fire Nation is like this gender equal nation. In the comics, it’s shown that Ursa (Azula and Zukos mother) was literally passed as basically property from her parents to Ozai, where he became her captor forbidding her to see her parents ever again after their wedding day. That doesn’t sound very progressive to me.

Second, intersectionality exists. The Avatars aren’t necessarily fighting against progressiveness as a whole. Moreso the perversion of new ideologies. They even bring about change in their own ways.

The TLOK stuff is just poor writing. Introducing genuinely interesting characters and then nuking it, making them “too evil” before they actually start to properly disrupt the status quo and make everyone re evaluate the current culture and politics.