To be quite honest, I do not believe in "non-violence" against bullying. If it gets to the point where I am physically abused by another person, I have no problem giving them a nice koshi-nage or a kotegaeshi. I must also be a bad person, because under no circumstance would the attacker's safety come over my own. If someone hurts themselves because they attacked me and can't fall safely, not my problem.
As my teacher says, "If someone steps inside your legal boundary and attacks you, whatever happens to them is a result of their stupidity".
It's honest and noble to try to "disarm" the attacker, but at what point should one risk his own safety at the cost of someone willing to do harm to him. Yes aikido preaches non-violence, but if someone wants to hurt me, I will do my best to defend myself, and am not going to just "sit on them in ikkyo" if they have a knife or a gun.
I don't consider myself a saint, but I don't consider myself a bad person either. I also wouldn't think twice about the fact that I could cause major harm to someone when defending myself if my life was at stake. Just my 2 cents.