That's probably broadly true in this specific conversation.I don’t think anyone is arsed that people decide to live however they do. Or they are what they are.
I think people are just poking a bit of fun at putting pronouns on the signature when it isn’t really relevant for most. Jokey faux outrage at most, no malice.
But it's certainly the case that people in more toxic corners of the internet, and in the real world for that matter, are certainly arsed about it and go out of their way to be as spiteful and generally as awful as they can to cause further pain to people who are already hurting.