Everyone chooses who they have sex with, or not have sex at all.
Right. People do choose whether or not they have sex.
They also choose who they have sex with - but just as I could not possibly perform the act of sex with an ugly hairy mutant of a man, a gay person isn't going to have sex with someone of the opposite gender. Choice is so thoroughly diminished as to not actually be choice, and I think most people who are actually alive and been touched by someone they're attracted to can recognise that.
Bisexuality aside, I think that's kinda easy to understand.
Gender is the same thing. Yeah, you can probably choose to live in misery and denial, but why? To appease some fuckwit? No, I don't think that's fair at all.
That's the thing - disagreeing with their politics is being framed as 'open discrimination.'
I'm actually a fan of Blaire White & another YouTuber called 'The Sphere Hunter,' and if I were to ever meet them I would use 'He/Him' pronouns. Because they 'pass' so it'd be easy to do so. If I were to meet Rachel Levine (and I would avoid it) I'd have to put on a hell of an acting performance to not laugh out loud before or after referring to 'her' as anything else but a man.
Trust me, if you don't do anything wrong to a trans person in real life, you won't be accused of open discrimination.
That's more likely to happen online, where people suffer from some kind of personality disconnect and assume they can argue (usually anonymously) without any reprisals, until they're otherwise doxed or identified.
But the same rules should apply, to be honest - if you wouldn't dream of being a colossal cock in real life, maybe don't be one on the internet either?
That's how I approach things, anyway.