I do think when a member continues to show a destructive behavior that is clearly demonstrated to be bad for the eccie members both in terms of privacy and personal risk (threats and activities) it does lessen trust/reputation of the site and can impact other (good) providers that are on here if this type of situation is not managed well.
You would hope that self policing these types of members would work across the community, but sometimes a site has to go further to protect itself and its members to whatever extent it can. P411 has done that. On eccie I would guess they are trying to figure it out (best handling options).
A permanent banning? I guess the question really is, what's permanent? The offender can surely find creative ways to circumvent the system either directly or indirectly as we see happen here occasionally.
Overall, I don't envy eccie or any site trying to deal with this type of problem.
Good luck