I only use Steam myself, so I hadn't checked Itch Io's communication yet. I don't know the platform myself so it's quite possible that I'm misinterpreting this, but to me it appears that Itch Io will allow creators to delist payment options that they are not compliant with: "For NSFW pages, this will include a new step where creators must confirm that their content is allowable under the policies of the respective payment processors linked to their account.".

Source: https://itch.io/updates/update-on-nsfw-content