So trans people existing is extreme politics, gotcha.
You are taking the discussion into a wrong direction, let's say I do a cyberpunk game and I decide to add a transsexual character, now that makes sense because you are talking of a modern setting and you assume time continuation from modern days but even on a modern setting, a person coming with "Hi, I'm a trans person and this is my history." after a stranger asking who that person is, it is extremely bad writing and virtue signaling.
Sorry, I'm against bad writing, doesn't matter the intention of the author, even if he thinks he will save the planet with this work, if his writing is bad, to the garbage must go. There is an old concept on fiction writing, the idea of the author self insertion and boy this is fucking bad wherever it happens, whatever the intentions of the writer were, most cases are authors making Mary Sue character that are just projections of fantasy of power from the author, other times are writers forcing characters to do things they never would do to force a plot point work and the list of writer mistakes on fiction goes on and on, the latest fashion of author self insertions is the cramming of personal causes on the most brutish, hackish and random way possible.
If you want to include a trans, you need to first make a discussion about sexuality on that setting, without that, it is impossible, are trans accepted? Are trans persecuted? How culture deals with sex change? How culture deals with sex? How culture deals with gender? How not to make that a fucking boring an unoriginal copy of modern life? How that fits on the fantasy institutions you are creating? And nope, some particular author virtue signaling on twitter (and out of the products he made) years later when the actual setting he made doesn't have an extensive discussion about it doesn't count.
I read a few attempts of including this kind of modern issues on DnD and Pathfinder before and all of those attempts sounded so fake, people doing stuff like having robot races not wishing to be misgendered without actually bothering to explain how that is even possible (the mind of a robot is different from a human being on that context) and this case is just another example of that. You have the problem of people been running DnD for years so they already developed their expectations on the setting AND the people trying to include this modern issues stuff show so little care and respect, their irrational hatred towards those bigots they see everywhere blinds them to the necessity of a bare minimum decent discussion on this.
I don't think most people would have a problem with people doing their new setting with trans characters and whatever but it is delusional to imagine you won't suffer resistance of including that stuff on the most hackish way possible on a setting that is running since the 80's.