I would hazard a guess that this is one step away from role-playing games (i.e. Dungeons & Dragons, etc.). And I used to work in that industry. The people gathering at the GameCons kinda gave me the creeps.
Ditto.
Many years ago I was a war gamer. Some of the shows, conventions, get togethers, etc brought people from all types backgrounds including a heavy role-playing contengent.
They always kind of creeped me out, too.