Well, a couple years ago there was a big kerfuffle about that in the news concerning PornHub. Apparently some content leaked past whatever moderating system they had in place. In response they simply removed a whole swath of content if there was no way to verify the ages of people in said videos and will not promote or allow uploads of anything they can’t 100% verify as being legal content. I imagine other “major” porn sites likely followed suit.

I can only imagine the amount of money a site like Pornhub pulls in on a monthly basis. Completely reasonable that they’d install a policy moving forward that anything unverifiable is denied a posting.