Why do conservatives think that the existence of gays is somehow an existential threat? I don't get it, how?

We just don't want gays to rape our kids, that's all. When gay rights were shilled as "it's just two people doing something in private" mostly everyone agreed with it, but in the last few years faggots have lost all their shame and flaunt their kinks in front of everyone, including kids. Before you say "B-BUT WHAT ABOUT STRAIGHT HYPERSEXUALIZATION?", that's a problem too.

fags probably didn't do much anal back then, mostly blowjobs

Rapid change is happening. That change is making communities uniformly worse while wages stagnate and decrease and the standard of living falls. We are a major part of that rapid change and get associated with it and frequently profess that all of the change is desirable and good.

gay people aren't external, that's the thing. other groups, though, very much can constitute external forces. i can't comment on american ideas specifically given that i'm not american, but families aren't exactly a new idea, i don't know what you're implying there.