This is where the line is. Feeling wronged is not sufficient cause for violence of any variety. Do I wish that we had sufficient technology that he would be incapable of harming your friend regardless of his intent and action without any grievous harm coming to him? Of course I do, but that's not the situation we find ourselves in. I agree with you on what 'should' be. There should be some way for a physically disadvantaged person to defend themselves in a life or death struggle with a physically advantaged opponent without killing them, but gives attacked party sufficient power to end the confrontation. We aren't there yet. We don't have a tool or weapon like that yet, and until we do, I don't see an alternative way to make things at all close to 'fair' in life or death confrontations like this one.He felt wronged, so he attacked.