i understand that is prolly part of it1. They're chastised in society so by being "out" they let the world know that THEY EXIST so they can't outwardly be denied legal recognition.
2. It takes a lot of courage to actually come out and be who they are so in doing so, they're reinforcing their personal confidence.
Its basically in response to how fukked up the world is to them. Don't blame them, blame the people who seek to discredit and remove and hide them away within society.