That's not why they do it. The reasons are regulatory compliance and risk. Processors would be in big trouble if they facilitate payments when they shouldn't, or broke due to rampant fraud in certain sectors.
I get that you might not like it, but take it up with the US government. The processors would be happy to move as much money as possible to make as much money as possible.
The legal structure has changed, but the boards of both are still primarily comprised of executives from other major financial services institutions.
Risk averse and sensitive to regulatory pressure by nature, the issue isn’t with Visa and MasterCard directly. They’re just operating in a space.
Somewhat ironically, Hock's "chaordic" management philosophy has strong parallels with ethos of decentralization held by some crypto idealists.
Mastercard and Visa don't block companies from processing because of morals, they block them because they lose them money. They will happily process your payments for all kinds of shady schemes that are - to them - low risk.
There are already laws (from actual governments) against human trafficking and illegal transactions. The issue is not about credit card companies obeying the law.