Lots of stuff on political leanings of posters
I don't normally agree with GreyWolfLord on a lot of things, but I think he is exactly correct here. Paizo is a pretty progressive company, and I think their support LGBTQ and moderation policies have gradually turned off Alt-right and more conservative leaning posters either completely away from the site, or at least from sections of the site dealing even tangentially with those topics. I've been posting long enough to see some pretty disgusting stuff be posted by folks no longer around, which quickly got deleted and in some cases led to bans. And just being the sort of person who spends a lot of time on a forum is going to automatically skew where you fall on the political spectrum.
I also think there is just a natural human tendency to assume whatever special interest you have, whether it's science, gaming, birding, or any other hobby, is full of like-minded "enlightened" folks of your political persuasion. And a lot of that is more down to hanging out in areas where those contrary folks don't show up, or conversations just not steering in those directions and thus a certain amount of ignorance of what other people really feel.