"Paysites: This should be plainly obvious, but apparently it needs to be listed here."

It's not plainly obvious. Someone didn't think that through when they were writing it. Every other prohibited content explains what is being prohibited. WTF is a Paysite? Are we not supposed to link to other websites where you pay money or something?

Parasites are organisms that latch onto a host to survive

Essentially, those are sites where you must pay to be able to view an artist's work. Patreon is a notable example.

This made me look at the TOS and like I’ve seen all of that “prohibited content” a lot