Is someone is actually attacked it is NOT an argument. I had issues with that on another site because a person constantly picked on me. If I ignored her she got 100x worse, and if I told her to stop I was told by the staff I should take my arguments into private.

Problem is it wasn't an argument. Compare to real life, if someone gets abused you don't put that person in a room with the abuser with no support.

If it is not allowed to protect yourself, it probably still is better to ignore than to go into private. If you do, you are on your own and that can be very unhealthy. Better pretend the attacker doesn't exist. And it is not against the rules.

IMO.