https://www.paymentssource.com...government-not-banks

Excerpt:

The suggestion that banks and payment networks should monitor or refuse to finance consumer purchases of legal firearms is a suggestion that banks take the law into their own hands. This is not only wrong from a practical standpoint (banks and payment networks aren’t great at law enforcement — they’re not supposed to be), it’s a step toward undermining the foundation of the rule of law upon which our nation stands.

Such proposals amount to a form of vigilante justice. If, as a society, we have decided that we no longer want to protect the ownership of certain types of weapons, we must work with our duly elected representatives to write and amend laws and decide how to reconcile that with the Constitution.

The prior resident of The White House's DOJ started this putting pressure on banks to stop taking deposits from gun industry manufacturers & FFL's. It was a part of Operation Choke Point but included payday lenders and those at higher risk of fraud.