The Fediverse is pretty radical. I'm an atheist also, an exmormon, and I think this might just be a misunderstanding.
The rule, "no LGBTQ+ content," I don't think is saying "no gay people." I am pretty sure it is just asking to avoid the topic, to prevent bigoted discussion from happening.
As fair or not as you want it to be, LGBTQ+ is a controversial topic for religious people, and I think it's fair to just put a pin in that discussion in your community. But what do I know?