

DS9 IMO is where the revisionism started.
This is directly connectable to two historical events:
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Death of Gene Roddenberry and control being ceded to other executives who were more liberal.
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It was the very first Trek show made following the victory of the US in the cold war, the end of history rhetoric and feeling reaching its height. (While most of TNG was filmed after the fall of the USSR, the first 3-ish seasons were written and shot before that, thus setting a tone among the writers, additionally the impact of the fall of the USSR wasn’t really fully felt until the coup in 1994 which was most of the way through the show’s run) Additionally I believe Patrick Stewart held some sympathies as the time that might have pushed back against any attempts to revise the universe, even if they’d wanted to and I don’t think they wanted to make any major changes during the run of the show.
This can be laid at the feet of Rick Berman really more than anything. Gene Roddenberry was weird, he was leering, but he undoubtedly had some much better politics than Berman and those who followed. In the glow of the victory of capitalism and end of history the whole IP took a very dark turn necessarily on the belief that this was it, this was how things would continue and Star Trek would have to exist in some related context with less utopianism.
Voyager continued or at least didn’t revert these problems though given it’s situation being stranded far outside of the communist controlled space their actions and activities can be more or less justified as frontier and war communism tough stuff. What can’t be as easily bushed aside is the black ops section whatever introduced in DS9, the heavy use of fiat currency among the crew in ordinary situations including gambling, and a lot of other shifts in how the federation is defined and run.
So I agree but I disagree in its inclusion in ST “golden age” canon which is basically just TNG. Hence why I think the IP is not worth fighting over, the liberals won long ago and it’s only ever gotten worse since then. By itself in a vacuum or with TOS TNG is a great if somewhat utopian socialist show. Everything that followed has been decay if not outright plundering in a mirror version of what Russia went through in the 90s of shock therapy and terror.
Definitely some so bad its good things to it. The director was a notorious Hollywood reactionary who was competent at making films at least. It’s not a great film, it’s clearly a propaganda screed and kind of laughable these days.
If you’re looking for other bad reactionary anti-communist films I’d suggest “If Footmen Tire You, What Will Horses Do?” if you can find a copy which was a kind of church/preacher-made fearmongering film about the threat of communism and a hypothetical scenario of what if they won in the US. It has this delightful scene where a communist commissar supposedly trying to indoctrinate a bunch of children prays to Fidel and “glorious Fidel” brings the children “all the candy they can eat” which consists of a guy walking in through a door and bringing a sack of candy the guy proceeds to throw at the children, telling them it is a miracle, not of “your Jesus Christ” but of Fidel Castro. This is a truly bad film unlike Red Dawn, Red Dawn tries and has correct communist iconography whereas the hammer and sickles in Footmen are badly done and everything is cheap.