TOS also has a way of contradicting itself more than not and the movies with the same cast said things that didn't mesh with TOS itself in terms of characters... also, back then, many things weren't shown on TV or couldn't be shown... and UFP wasn't really fleshed out (that's why other series like TNG started filling up the void).
Trek is still very much limited in aspects of the real world and in some cases trapped by the limited mindests of the writers who grew up in today's system (or in the case of TOS, writers who grew up back then - which was arguably worse).
Whoever wrote the notion that celebrating man for being a savage at heart should have had their head examined and did NOT know anything of behavioral science or how environment shapes behavior... they seemingly injected the notion that humans are bad from birth... effectively, that we are born like that and that the only reason Humans in the future didn't behave like that is because we fight against those impulses.
Such a gross misunderstanding.
But this also came from the people in 1960-ies USA that had a certain perspective of the world and where Uhura was almost treated as a glorified secretary and she wasn't really involved in any major decision making (though she WAS part of the main cast and had far more exposure for African Americans and women in general - which I suppose was considered 'progressive' for back then - the movies arguably gave Uhura a bit more prominent role because times have improved by that point since the 60-ies).
Nichols wanted to seemingly quit the show after the first season given how little she was given to do and the indignities she suffered at the time... and it seems it was because of a conversation she had with Dr. Martin Luther King that she remained on the show.
So, I'm not sure if TOS should be the best indication of these characters pasts because it seems like most episodes took place in their own alternate universes.
My take is you have a very TNG view of the Federation that wasn't the case in TOS or the DISCO and SNW period.
Basically, I don't think your opinion is WRONG but you are saying, "Ignore everything that contradicts my point. It should be this way, regardless of canon."
And the person who wrote the episode glorifying savagery was Gene Roddenberry.