While false positives are a fact of life with any filtering system, they have no incentive to FIX the problem, as those false positives lead to their being able to hold funds indefinitely, earning interest at least, and potentially absorbing the entire balance.
This is called a moral hazard, and it should be pretty clear to you.
Paypal has a very long, very well documented history of triggering holds on accounts, and never resolving them.
The terms of service clearly state that sites of a sexual nature are not accepted.