But simply enable pm only after 2 weeks.
This will have extra benifit that those who make new account after being banned will have to wait 2 weeks before they can pm again
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That would discourage new members, and like I said before, idiots will always find a way to be idiots. This global social media problem won't go away until the nature of humanity changes.
One last point: I've noticed that a lot of bad users are <age kids (because most sites don't have age verification) or guys from countries where the attitudes toward women are more sexist and primitive.