This isn't exclusive to our community but in general, people tend to make anecdotal suggestions or opinions based solely off their own experience bias.

I would assume that whomever suggested that must have had a bad experience with 1 or a few gay men and that in turn means they now condemn any and all gay men as being transphobic. And therefore they now feel like we should be excluded entirely. But that's not how real life works.

Realistically speaking, every single person is different. No one's gender, sexuality, race, or biological sex is the whole sum of who a person is. It's just one part of the synergy that makes up individual humans. Not all gay men are transphobic, and not all gay men are friendly toward trans people. It all depends on the individual. If we focused on that and stopped putting people in monolithic groups based on one aspect about themselves that they can't control, then maybe our community wouldn't have issues getting along with each other.