You are either disingenuous or fucking retarded. The moral of a story where there a just King defeats an evil Tyrant isn't:>Kids, we should replace our democracy with absolute monarchy, look how great it turned out!
You are just conflating elements of the narrative with imaginary propaganda to smoke-screen OK KO's actual propaganda, because truthfully the only person who is unfairly biased is you.
The Air Nomads are a peaceful culture that abhor killing. The Fire Nation has a monarchy. Ba-Sing-Se is ruled through class segregation and deception. These are just facts of the fictional universe, the viewer is allowed to form their own nuanced opinion. The Air Nomands were nice, but got obliterated because they had no military to protect themselves. Zuko became a wise and patient ruler, but they just went through 3 generations of bad ones who unleashed a century of war. Long Feng is just a shallow villain, but if you want to suggest that "kidnapping and brainwashing people is wrong" is propaganda than both you and that word is useless.
OKKO's "Skeleton Remote" episode makes no fucking sense. It takes place in a universe where violence is glorified and lethal point-and-shoot weapons are readily available. No one would seriously suggest OKKO was propagandizing vigilantism and tank ownership. Yet suddenly when they get these remotes they lose their collective shit, start attacking people wantonly, and then the episode ends with direct preaching to the viewer to contact their political representatives. It's a little bit fucking different.
I can even give you a better case for ATLA - Sokka is a chauvinist while Katara is feminist, yet they both grew up in the same shit-hole igloo village isolated in the South pole.
If the culture is male dominated, where did Katara learn to be so progressive?
If the culture is more egalitarian, where did Sokka learn to be so based?
The answer is the writers didn't care, they just wanted girl power episodes.