I don’t like the way “transphobic” is thrown around – when often, what’s at work is ignorance. When I talk about non-trans attitudes toward trans people and identities, I refer to it as “trans etiquette” – as in, give people a chance to learn how not to be ignorant and rude before deciding they’re transphobic.
If they persist in re-gendering people, asking surgical status or for a “real” name, then they’re just assholes.