Unfortunately, as long as they're relying on Stripe and PayPal there are 1imitations to what is and isn't allowed: there are plenty of things that US payment processors make hard to deal with.
Not trying to dispute your point, but out of curiosity: Is that actually true?
> Donations to [...] can be paid using: a credit or debit card (Visa, MasterCard, American Express), a Euro bank account (SEPA Direct Debit), or a PayPal account.
Could I send money through my regular European bank without using Stripe to pay on Liberapay? Does anyone know how they've implemented that?
However, Stripe is still a US payment processor, and will be subject to the same legal concerns as other US payment processors (such as those raised by FOSTA-SESTA for anyone involved in any sex work). While you might avoid Visa/MasterCard's rules that come from such a legislative environment, you won't avoid Stripe's.
