Patreon is not a "payment gateway", it's a mechanism for people to support creative activities, as the original term "patron of the arts" means.
Funding military weapons steps on some very complicated lines about what people are allowed to spend their money on. So saying "what private citizens do with their money is up to them." is only true as far as the law says.
Sure, but Patreon was just fine with this until two weeks ago. They should either work on their acceptance criteria or admit that they are in fact a money transmitter. They very selectively enforce this and that is why it makes them look bad because right now is the worst possible time to close this account.
Funding military weapons steps on some very complicated lines about what people are allowed to spend their money on. So saying "what private citizens do with their money is up to them." is only true as far as the law says.