Well, obviously from a business perspective Patreon shouldn't do anything about it. But what
dolfe67 was suggesting is that it's what they'd like to see Patreon do. In other words, morally speaking, it would only be fair to supporters to get monthly posts from creators or their account gets closed.
Personally, I think it's unreasonable that the account get
closed (that's too harsh), but I do think it should be something like auto-renew for monthly billing is stopped if there's no post. In order for it to restart, a post would need to be made. I do think that's reasonable, in terms of fairness. However, from a capitalistic perspective, they obviously have little to no reason to prevent themselves from getting regularly paid via their creators.
Honestly, if services like PayPal and Stripe didn't have specific rules in place, Patreon wouldn't be restricting any content that's not illegal in the United States. They follow the money, and if payment providers threaten to stop payment coming to them, they'll bark and clap like seals until they've paid proper obeisance to the payment gods.