It's also possible that while it might not be against any discrimination law, the legal told them to not allow General Flynn to take it to a court for a judge to decide if it did or not because then they would be on the hook for this and possibly many other account closures.

Additionally other payment processors could have gotten on their case because if precedent was set then places like Paypal and other banks would now be forbidden from doing that to anyone.

Sort of like if Burger King was going to do something big and then Jack in the Box, Wendy's and McDonalds came to them and told them not to because it could hurt all of their businesses in the future.

We all know places like that collude with one another so the idea that if one was going to screw up in a way that affected them they'd step in and try to get them to stop.