I can say I find my bank refusing to honor my self-identity as a millionaire as creating a hostile environment for my life. But clearly that's ridiculous.
Similarly, someone using normal English third person pronouns can never be 'hostile' in itself. There would need to be additional behaviour or slurs used, in which case the pronoun usage is irrelevant.
It is not creating a hostile environment using normal English. I actually think that suggesting to young people - especially those from lower socioeconomic backgrounds (e.g. those in care) - that they can expect to compel the language of others throughout their lives and that not complying is hostile and hateful is in reality itself quite hostile because it's setting them up to fail in normal everyday life. It's creating mental health problems.
Old school transsexuals knew (and still know) the sex they are. They don't expect other people to pretend they're literally the opposite sex, just be treated as the transsexuals they are with normal human levels of dignity and respect.
I do understand that the children of celebrities may really be able to punch down on their cleaners, cooks, HCPs etc and force them to say whatever they want. So it has always been, but let's see that for what it is.