They’ve posted an update stating that the reason they’re doing this is a switch to separate CC charges for each pledge, rather than having them all grouped together. And why are they doing that? So that they can bill immediately, rather than only at the start of the next month, which apparently is important for the “Patreon as a paywall” use cases.
So turns out they’re not actually greedy assholes. Instead they’re total morons who didn’t understand where the value proposition of the service was. Unfortunately the outcome is still the same; I canceled half my pledges.