I don't think it's crazy for them to be here. The games, banter, and everything else on this site is fiction.
As an example, I've played plenty of GTA games, and I really don't want to do most of the stuff that I love doing in game. I pick up hookers in GTA games, but I have zero desire to do that in real life. In GTA, you fight with gangs, cops, etc. and I have zero desire to do that in real life. In plenty of games, I get a good laugh getting my characters fucked up on drugs and alcohol, but I don't want to get anywhere near those levels of fucked up in real life.
What I think you've somehow missed here is that for many of us (most, I hope), this is all fictional stuff.
I also watch some of the silly pornos where step-family stuff happens. It's fun, funny, and taboo in the videos. I have zero interest in doing anything with someone who raised me, I was raised with, or I'd be raising. Zero.