But that's not the point is it? The point is that Mastercard and Visa are facilitating the transfer of money for illegal transactions. In the same way you can't start a bank to facilitate money laundering, Mastercard and Visa cannot knowingly facilitate the transfer of money for illegal goods.
The problem is they are going beyond what’s illegal and cutting off usage/content they just don’t like for whatever reason—see the vampire porn example in another comment, wikileaks, etc.
Do we want unaccountable monopolies making decisions about who can access the financial system and who can’t based on their own subjective values?
I mean there are certainly alternatives to Visa and Mastercard. Credit cards aren't the only way to pay for goods and services. PayPal and Crypto being the most common. For personal transfers there's also Wise (which you can do person-to-person instantly), and if you live in some countries there's stuff like Interac E-Transfer for making personal payments. If worse comes to worse there's bank transfers and ACH, which are accessible from virtually any bank.
I see Visa and Mastercard like Facebook, Twitter and Instagram and they seem to have the right to refuse service to anyone they want to.
There should be something like a safe harbour / common carrier provision. We recognised that this was vital for postal and telephone networks, that the benefits of a neutral network outweighed the costs of carrying crime sometimes. It should be the same for money transmission.
