Under that aspect, "gay culture" emerging like a culture of some people being childish and ridiculous, I can really understand that Eastern Europe and Russia rebel against it.
I don't know how it became this way, but regarding the rainbow flag and what is linked to it independently of the circumstance of being gay itself, it seems to me like something one can get more happy with as a regular citizen.
You are gay or transgender, but you're no part of that circus. It's got nothing to do with both things as a subject, it's something that others try to sell you as "gay culture" and "the way gays are naturally".