Well I don't know what to tell you aside from seeing a lot of posts on trans subs where OP would be like

Why do gay men hate trans women? I got told by someone in a LGBTQIA+ sub that I was just a a confused gay guy?

And the comments would be filled with people guessing

"This was /GayBros wasn't it? They are like that, Gay men as a whole aren't."

I won't argue with your experience, but at minimum that sub DEFINITELY had a reputation.