They're playing the game of trying to ban some of it but not all of it. For erotic literature specifically, they're trying to forbid certain genres. It's a weird cat and mouse game and I'm having trouble picking sides.
I'm generally upset at them over their weird ban-not-ban. I can understand they have to deal with credit card processors, etc - but please give the community clear guidelines and don't play the part of the censor.
I'm not certain there's a way out of it. On Quora I've been seeing pedophiles creating accounts with the intent on pushing boundaries. It's pretty disturbing seeing it taken out of a literary context. I don't envy Patreon's task here.