Sorry, who do you believe is preventing Stripe from charging higher fees to riskier accounts? Please be specific.

Also, what's your evidence that some payment processors don't handle porn because of government pressure, rather than just natural market forces? I had a friend who did tech for a porn company, and from what he says, even a well-run porn company has much higher rates of chargebacks (e.g., next-day regrets and "no honey I don't know what that charge is") and fraud (stolen cards, fraudulent affiliate program participants).