If you want to be an asshole at home, you're free to do so insofar that it is legal. But if you want to be an asshole at work, that should not be enshrined in the same way as religious belief as pg suggests.
Unless you think it should be allowed, but what level of assholery is allowed? Is assholery against trans people the only assholery allowed? Is it okay to be an asshole to disabled people too? To women? To someone of a different color?
By the same logic as you are presenting, it is toxic and hostile to impose this ideology upon others. If believers of this ideology want to use "preferred pronouns" and such, they should of course be free to do so.
But others who do not hold this ideological stance, including those who oppose it for whatever reason (e.g. because they see the concept and implementation of "gender identity" as fundamentally sexist), shouldn't be forced to pay lip service to it, any more than atheists should be forced to pray at work.
You call this refusal "assholery", but presumably that is because you are a believer of this ideology - including the belief that to reject it is "transphobic" (which is roughly equivalent to the religious zealots' cry of "heretic") and therefore, per this belief, reprehensible?
It's more like if he introduced himself as being a young child or a dog. No-one should be under any obligation to play along with Bob's claims to be an infant or a canine when he is neither.
I would ask, when denying people their self-determination, does it start and end with trans people, or is there more? If someone is raised as a Muslim and converts to Christianity, do you deny them that? Who is the arbiter of who gets to decide who gets self-determination and who doesn't? I doubt billionaires, nor politicians, are the best authority for that.
Also, keep in mind that you're railing against one of the smallest, and most persecuted, minorities on the planet. Why do this? Were you harmed by a trans person in some way, or were you just told to do this by someone on social media? Have you met a trans person and talked to them about their experiences?