Devil's advocate: are you really paying them for a service? I guess it depends on if you pay your bill in full each month, but for those that do pay in full, credit cards provide so many "free" benefits (travel perks, cash back, loss protection, extended warranties, so on). So for those, credit cards provide excellent services requiring no payment at all--it could almost be seen as a club with benefits that one joins, and if that's the case why not impose their moral compass onto its members (like most clubs do)?

That said, I generally agree with you.

As the article outlines, they already do by not allowing you to purchase cryptocurrencies.

I don't see any logical reason why "I'm paying them for a service" means they can't impose restrictions on the service they offer, except in the case of a monopoly, in which case there may have to be regulations on this.