I'm on a few forums, not just in Audio. I have to ask: why are you making it your problem? If you insist on living your life from the outside/in & not the reverse, you're in for a world of never-ending pain. Who's then most responsible for this state of affairs? Exactly.
When I run into someone especially noxious, vindictively reactive & frequently so, I very occasionally use the nuclear bomb. It's this:
Rudeness is a very weak man's imitation of strength.
BTW, DO NOT say this to someone very rude in-person. The chances of it leading to a physically violent response are not negligible. Seriously.