I agree with others that we need to make users accountable for what they say by disabling unregistered posting. Any long-term fix needs to start with that. That should be enough of an impediment to discourage casual trolling. Obviously most unregistered users don't cause a problem, but we should prioritize fostering a sense of community over simple ease of access.
I guess I'll message this kotono and see what our options are. But he may very well not even check these forums, in which case we'll need to find some other liaison.