The problem comes from "legal transactions".

The Pornhub problem came from going after the payment processors for facilitating supposedly illegal transactions--namely, underage porn. The crusaders (in every direction) keep looking for ways to undermine the protections (Section 230 in this case) and all too often the government doesn't fight back.

As for keeping it in the family games--we still have "obscenity" on the books and such games fall afoul of it. I find the concept of "obscenity" bonkers amongst consenting adults.