Money, the payment processors and credit card companies do business in countries that completely ban the kind of stuff that got put into the new rules and payment processors and credit card companies are where Patreon makes the big bucks. Any website that allows such content is under threat from payment processors and credit card companies to not be allowed to use their services, which can cost those websites A LOT of potential customers. That's why SubscribeStar doesn't have those options.Incidentally do we know why platforms do this? It isn't just Patreon.
The closest thing to a cogent argument that I've ever read was that apparently with adult content there tend to be more chargebacks, but I don't even know if that's true.
Back in the day I would have assumed it was just due to pressure from certain groups but those groups are no longer in the ascendant, and while there are certainly others that have picked up the torch with equal (or even greater) fervor, they don't (yet) have the same sort of each as their predecessors.
Do the numbers just work out behind the scenes in such a way that more money comes in if everything is 'squeaky clean' so to speak? I find that kinda hard to believe, but what else is there?
Those certain groups are a problem to be sure, one of them is what caused the Intch.io issue, but they are not why the new rules are in place. Groups like that don't have enough influence to make sites like Patreon bow down, but payment processors, like PayPal, and credit card companies, like Visa, do.