Except there isn't a duopoly in online payments. In fact, Stripe is just one of many (and not anywhere near the largest) payment processors[0].
[0] https://www.business.org/finance/payment-processing/largest-...
Why must it be through an online payment processor?
My bank will send payments for me. And I can write a check and mail it to whoever I want.
you don't really believe what you're saying do you? that's like telling blacklisted hollywood writers and actors that they can make their own plays in their backyards
We're talking about a candidate's campaign fundraising operation. Which is odd in and of itself, because as far as I know that candidate isn't actually running for any office.
You've moved the goalposts far enough, haven't you?