The “gap” is a customer choice though. I ran payments myself in 1999 and had to get a merchant account and deal with the bad APIs of the time. People can do this today. Or use Stripe. Not a great choice, but still a choice.

What specifically is the regulatory gap here?

'due process' concerns around sudden blocking of routine traffic -- should platforms give notice, are they required to justify the ban in terms of their TOS + enforcement history, what is the time scale of appeals, can customers appeal to an independent body, and reporting transparency for enforcement

This. If you’re providing financial infrastructure, there should be exception recourse versus customers having to come to public forums to beg for help. You know, like banking regulation.