I know you basically agreed with me here, so this is kind of a pointless comment, but I was thinking more about it and I think that Avatar: The Last Airbender did a better job on this front. Sokka is sexist, but in THE VERY FIRST LINES OF THE FIRST EPISODE he is called out on his sexism, and then later he has a whole storyline about respecting the Kyoshi Warriors and not dismissing them for being women. So like, it's realistic that Sokka is sexist, but the show makes sure he doesn't "get away with it," so to speak. I would have liked more of that from the earlier Buffy seasons.