SO my question is, what is it about the LGB community that makes so many people lose their damned minds and try to infiltrate us? They don't even like the same sex so it makes no sense. It's like someone who doesn't like cookies trying to forcibly gain entry into the cookie lover's club by pretending to like cookies. Like.............. Why????????????

I, too, keep asking myself this question! Especially since the combo of being both destructive and inexplicable is the very definition of distressing.

Here's the best that I've been able to come up with:

First, I think that-- like the trans/gender-woo disaster as a whole-- this is probably the result of not just one, but multiple factors. (See the U.S. opioid epidemic, as documented in Sam Quinones' book "Dreamland", for another thoroughly-dispiriting example.) So, re: everything from all the other commentators: what they said!

Second, to bring my own contributions to the table:

• Identity politics: you are what you "identify" as... regardless of anything else (like, oh, I dunno, WHETHER YOU MEET THE FUCKING DEFINITION). Or "feelz > reelz", in other words. (I suspect that this is a subtype of the general rationality = ick/emotion-trumps-everything attitude that's been on the rise among lefties for some time now; see also: anti-vax.) Which makes it entirely possible for a man or straight woman to be "lesbian", women to be "gay men", etc. But of course this only helps explain the "how", not the "why". Which in turn leads to:
• Het Is Ew: somehow, this attitude seems to have become weirdly-prevalent among lefty/liberal/progressive straight people. As in I've seen 'em actually apologizing for their straightness on some SJW-y sites. The feeling seems to be that, unless you're SSA, you're insufficiently "woke". As well as kinda sexless (unlike us big ol' LGB pervs). All of which is not unrelated to the gay-trendiness factor, of course, but I think that this specific manifestation is slightly different: less fun/frivolous, more insecure/guilty.
• confusing accoutrements with essence: mistaking the trappings of LGB for the thing itself. So having a blue undercut = "gay"... even though you're exclusively attracted to the opposite sex. Simply take on the stuff associated with LGB culture and you are LGB... somehow. No idea where THIS idiocy came from-- identity politics? rampant commodification/commercialization/merchandising? omnipresent media? (with its trafficking in simplification/shorthand, notably stereotypes)-- but it's certainly here now.
• straight entitlement: much like the more familiar male entitlement-- heterosexuals' privilege (due to overwhelming-majority status and cultural dominance), including their obliviousness to it. Which allows them to casually appropriate our sexuality without bothering to think of the implications, such as what that might mean for us. And, moreover, do so in a way that emphasizes outrageousness/freakiness, since this is an adventure for them, and their own sexuality has a built-in assumption of safety (being accepted, indeed the default) that ours does not. To us, that's the normalcy we strive for; to them-- since they take normalcy for granted-- it's just boring.

These are some of the things that occur to me re: WTF, straight people???, anyway.