If (big if) that’s true, then San Fran would be at the extreme in terms of having a queer community so large it can ‘afford’ to ruthlessly exclude as you experienced.
Likewise with diminishing religious groups becoming more tolerant and welcoming.
Then again, some of the teeniest subcultures are notorious for elitism, maybe it’s a bell curve.
>in many cities the queer people all know each other
is massively untrue based on my own anecdatum. Where I'm from, there is certainly a group who all know each other, who hang out at the gay bars, and who seem to have dated many others in the same group at some point. I have seen this by snooping on instagram or facebook - the same set of faces shows up at any gay event, and they do all seem to know each other.
I assume you're in that kind of community in your city. I'm glad for you. I'm certainly not within my city, although I've had "encounters" with people in that group. Given the significant percentage (3.5% according to google) of LGBT people in the population, I have to believe the vast majority of LGBT people are on the outside of any such group you're describing. Our social life is probably drawn from much more average sources (work, college friends, possibly church) than what you describe.
It's not organized per se, but in many cities the queer people all know each other. I live in a big city with a big queer scene, and I can't tell you how many times I show up by myself somewhere only to see 3 or 4 people I already know there. Or find out that the new person I'm dating is besties with another friend. We all have pretty similar politics, but we also never talk politics or current events (that shit is depressing). Conversation is largely about our own lives and relationships, which IMO is how it should be. The focus is on making space for and supporting eachother, not winning an argument.
If you're struggling to break in to the community, just set up a dating profile (Grindr if you're a gay man, OkCupid if you're not) with something along the lines of "baby queer here, I need friends". People will reach out to you because we've all been you. I have found people in the LGBT community to be incredibly caring and willing to invest in people they barely know, simply because they remember what it's like to be alone in the wilderness. Community is how we heal, and intentional family built one relationship at a time is stronger than relying on circumstances to provide you with social ties.
Much love, get out there and get involved, let yourself be vulnerable, and you will find your people <3