There is such a wonderful thing as the law, which strictly defines what citizens can and cannot do. If the law and the courts recognize NSFW art as legal, then that’s it. An avalanche of toxic comments cannot be above the law, or we’ll slide from democracy to fascism, where an angry mob dictates laws, stomping into the ground anyone they don’t like.
visa and mastercard are acting vilely, dictating their judgments about what content they allow and disallow to be paid for. Their job is to control the legality of funds, not to judge what people are paying for. If something is legal under the law, they don’t have any right to ban it simply because they don’t like it. Content platforms decide for themselves what content to allow, and financial companies should control the transaction process instead of blackmailing other businesses into doing what these companies subjectively - not legally - think is good. Someone should sue them for acting like they have the right to write their own laws above the state.