I think you're right about that being the origins of the joke, but the joke is distinctly trying to infer the reverse. Funny in context, but out of context, it's just an obnoxious over-association leaking out of a community.
It's as stupid and culturally braindead as the old 2000s jokes where the entire punchline is the gay guy is flamboyant. haha gay rainbows! Ver funny!