scamper

I would probably call them ‘boards’. Communities is too long of a word imo and it makes it sound like the people subscribed all have some kind of shared culture or relationship. That definitely happens in some cases (there are subreddits which have built a community around them) but it’s not universal.

You might call the category lived experience. Does your gender identity match your lived experience and upbringing, or does it not? Sometimes you see trans people use the phrase ‘man of trans experience’ or ‘woman of trans experience’ to highlight that the word trans applies to history and experience. So the question might be, “what is your gender experience?” or “what is the nature of your gender socialization?”