It's not just them. For example, 4chan is a surprisingly good way to get the most recent scoop on good models (both text and images), setup guides etc - if you can tolerate the inevitable, well, 4chan-ness of it. And the reason is exactly the same: a lot of people there really, really, really, want to generate porn and to chat with sexbots, and they're putting a lot of effort into getting the best (and least censored) results out of the resources that they have.