Strongly disagree with the take in the OP, to the point where it feels like you played a different game entirely. This is coming from someone who was massively disappointing in Life Is Strange 2 and criticized it specifically for its cringe worthy political commentary and non-stop straw conservative caricatures. Tell Me Why handles its issues FAR more adeptly than Life is Strange 2.
When is there ever a political position advocated on the basis of Tyler's gender identity? Unless by identity politics you just mean "having a trans character at all."
Also, there are numerous straight characters who are presented as decent people. Even the ones who are insensitive towards Tyler are still humanized with sympathetic aspects. Eddy Brown is affectionately praised by Alyson and is shown to be accepting of Tyler despite their issues, Tom Vecchi is portrayed as a perfectly pleasant normal dude, Alyson is straight so far as I could tell (mentions having an ex boyfriend) and she, of course, is portrayed positively. Hell, even Sam, the person who comes off really badly in regards to Tyler's trans identity is still shown to be a caring dude who took care of the Twins' house and cared after their mother. He's not portrayed as some monstrous bigot, just a guy who is down on his luck, behind the times and winds up saying some insensitive shit. Tyler can choose to lay into him or be more cordial depending on the option the player chooses, so you can even opt to try and meet him half way.
So where are you getting this "all straight people are bad" thing? It's seriously not in the game.
...Except for all the characters that are accepting of it?
What are you talking about? Thats in no way portrayed in the game. Tyler explicitly mentions all the people who accepted him while he was a mentor. He mentions that they helped him feel like he had a home. Within two seconds of meeting Micheal they're bonding over their mutual love of fishing. In no way does the game portray that "everyone is against you, nobody will understand you" if you're trans. This is in your head.
At least study? You legit find out that she was accepting of Tyler's gender identity the whole time. You confirm it if you successfully solve the dialogue puzzle with Tessa. Which makes it really funny that you bring up the mother as an example of there being no nuance to anyone in the game. The whole story of their mom is that she may not have been the terrible person they assumed she was. Legit the most overtly transphobic character in the game is given depth, nuance, and a potential redemption arc. How are you bending that into just another person against Tyler?