I think it's mostly what they find or get so negative backlash that they have to do something. I've played 2 games that are on Steam that have non-consensual sex, one is few scenes with violence (Dessert Stalkers) and another one where you have the chance to enter in a room of one girl and having sex with her while she is sleeping (knightly Passions).Steam seems to be
Steam seems to be very arbitrary with how they apply their "rules." They claim to be against non-consensual sex acts (and I'm ok with that, personally) yet they have kinetic stories on their site where men a forcibly sodomized routinely. I really don't understand what their standards are and how they are applied.
Honestly, I don't know how an AVN author can keep up with the Steam policies; perhaps that's by design.