In this story, Itch and Valve are 10x more trustworthy than the card processors.

The fact that Visa and MasterCard are the primary payment options for OnlyFans, makes this story a mess. Some time ago Visa and MasterCard very vocally banned Pornhub (at least) from using their cards, 100% sure this comes from them.

You mean like this?

https://www.theguardian.com/uk-news/2021/aug/19/onlyfans-to-...

Ultimately the ban was undone in exchange for onlyfans limiting the type of content available on the platform. So effectively, payment processors dictate which type of sexual activities, performed by consenting adults, are OK to depict and sell. Why? Why do they have that power?

The government historically uses the the financial industry to police crimes and behavior that it does not want to or that it is not expedient to police directly. Clearly they like the outcomes of the payment networks' rules and enforcement decisions and see no need for things to change.

> Visa and MasterCard very vocally banned Pornhub

Not exactly. Visa was named as a counterparty in a class action against Mindgeek for monetizing child porn on their website. They lost, and there have been subsequent class actions.

> Some time ago Visa and MasterCard very vocally banned Pornhub (at least) from using their cards, 100% sure this comes from them.

That was because the government was prosecuting Pornhub for breaking the law (rape with real people, unlike these games).

Oh 100% agree there. It's who they have to deal with who are the problem.