No, absolutely blame the payment processors. You think these clowns are the first to write them about it? They (the pps) even tried to force only fans to ban porn a while back, but for whatever reason backed of in the end (somebody probably had a second look and saw how much they really were making in fees there).
You can also still by all kinds of nsfw stuff with your card, so it definitely aren't the optics they care about. Christ, nobody even considered Visa etc. to have an image before this, they were just an unobtrusive middleman.