They may not be de jure be public utilities but they are de facto public utilities. It is essentially impossible to live in society without them, and outside their collusionist cabal there are no real alternatives.

Agree it disagree with them, but don’t the payment processors get a say in what they do or do not want to process?

Absolutely not. Power companies don’t get a say in what the power they supply their users with is used for, same for water companies and even ISPs. If they really, really want to enforce rules on what they will and will not process payments for, they can accept legal responsibility when they process a payment on a gun someone uses to shoot up a school or what have you. But they cant have it both ways.