On the other hand, if quite a few people just prefer to watch the version with a white man, that seems like it would correlate to the shows being cancelled, independently of how entertaining they are..
Supergirl started as a nice show that was promoting female power, but at the 4th-5th season transgender and black women started to appear just becuase they are transgender and black, and men characters got dropped out of the show just because they are men even though they were very good team companions to supergirl.
Also for me it's boring to hear how much women don't need men instead of seeing an interesting story.
The other problem with subsequent seasons with lots of PC speech is that viewer counts drop because of the boring story line, and then of course the series gets cancelled.
That space force comedy with Steve Carell comes to mind
I don't think it's a political agenda. I think a sizeable portion of people just like seeing this stuff that affirms their beliefs or gives them an example to point to. Conservative leaning stuff does it too, and it's even more annoying when you disagree with its themes. I recall Logan Lucky (movie) was an especially aggravating example of this on the conservative side.
It's the difference between making a film about black Peter Parker vs. (black) Miles Morales for spider man. If they go for Miles, great, sounds like a good start. If they go for the former, you really have to wonder why, and how big of a deal its going to be. Being talked down to with drudgingly obvious and childishly simple messages about racial equality is annoying. It's so, so much better to demonstrate equality by having competent outcomes from a diverse cast.
I enjoyed "The OA" and "Snowpiercer", I really enjoyed "Devs" and "Watchmen". I don't mind female characters. I don't mind non-white characters and I don't mind non-straight characters.
But I get really annoyed when they seemingly shove those things in my face just because "yay diversity!".
Have the main character be gay or black or whatever, but if it's not relevant to the story, just treat it like a matter of fact and have them act like real people.
Dragon Prince is one example. Cute show, but very in your face.
Old 80s sitcom Dinosaurs, ran into the same problem. Later episodes often made you feel bad. Not the best for a comedy show.
You can agree with a stance, but you don’t always want it shoved down your throat.
Oh look every cast member is a different race/ gender/ orientation. Oh great, but is the show any good?
Maybe that has something to do with it. There is a common meme "manga, anime, Netflix adaption". The first two show the main character looking as designed, and the last show a black woman. It ends up, if you optimize for showing every race and gender rather than entertainment, I can see why the show would be cancelled.