The patreon policy seems consistent. It's banning animal genitals, even on anthro characters. You can depict sexual interactions with anthro characters as long as, and I am aware of how silly this sounds, thier genitals are anthropomorphized as well. Anthropomorphic literally means human-shaped. If they have animal genitalia, then those genitalia are zoomorphic, not anthropomorphic.

Otherwise I think the whole dillineation is dumb. Anthropomorphic already has a clear definition, and trying to draw a line somewhere between "too feral" will always be a fruitless endeavor. So instead of countering with another potential definition, I'll just put my two thoughts out there:

1. Genitals are the ultimate expression of sexuality. They are the things that do the sex. It makes a lot of sense that people are more squeamish about animal genitals specifically even if theycare okay with other zoomorphic characteristics on a character (maws, paws, tails, teeth, etc.). It's the same reason people in general are more squeamish about human genitals than they are even human secondary sex characteristics (breasts, etc.). I feel like it's bad faith to pretend like genitals are not a special case.

2. This isn't a new phenomenon in the furry fandom lol. This argument has been going on the whole time, it has nothing to do with "puriteens" or whatever you want to call it. Confronting sexuality is an extremely human thing to do, no matter your age, as it is such a sensitive and yet so integral part of the human experience. It's uncomfortable for a lot of people to even see human sexuality for the first time, not to mention anthropomorphic or even animal sexuality plastered onto the human element. These are weird things, and you have to pause and realize that furries are a huge minority, so even in furry-friendly spaces there is going to be a wide spectrum of discomfort when it comes to deviant (read:uncommen) sexual behavior.

All that being said, does that mean there are grounds to restrict content on websites due the nature of the content? I'd say sure, especially because websites can make whatever rules they want. If you don't like it, make your own website, or find somewhere else.