In a nutshell, an Australian anti-porn group put pressure on the credit card networks Visa and MasterCard, which process the grand majority of card payments worldwide, for both credit and debit cards.
https://www.thepinknews.com/2025/08/04/visa-mastercard-adult-purchases/
What remains unclear to me is why a somewhat obscure lobbying group was able to bring two American multinationals to heel. But in any case, I am of the opinion that this group sits well within the range of right wing reactionary, in spite of dressing itself up in the cloak of feminism. The group's Wikipedia page lists the founder as a conservative and anti-abortion activist.
As usual, Wilhoit's Law is instructive: this despicable group seeks to denigrate sex work, depictions of sex, and the legal market for sex art and anything arbitrarily similar, by denying this group of people from the financial system and from earning an income, and then leave them without any support or even a suggestion as to what these people should do instead. This is the "bind but does not protect" part of Wilhoit's Law. No different than American conservatives and TERFs that try to drive a wedge to isolate trans people, this group targets sex workers and they cannot be allowed to continue unabated.
The legal solutions are as straightforward as they seem: require that interstate financial services can only charge a fee if transactions are routed and processed neutrally. The economic solution would be the expansion of existing national payment clearing networks (ie ACH in the USA) to also process card payments as an alternative to the duopoly.