Here's an example: My sons like to swordfight with sticks. One day I saw them whaling at each other particularly hard, and I stopped them and said "Guys, if you don't tone that down, one of you is going to end up bleeding, and I'm going to punish the other one."
So they calm down for two or three minutes, but gradually ratchet back up to whaling at each other again. Presently I hear WHACK - "AAAAAAGGGHGHHHHH!!!" and my seven-year-old is crying his head off and one of his fingers has a crushed nail where his brother's stick-sword caught it just right.
"I told you that was going to happen, and now I'm going to punish you for it," I tell the older boy.
"But it was an accident!" he protests. "I didn't mean to do it!"
"You didn't mean not to, either," I reply.
You see, if he had meant not to, he would have done something different. And to that degree, this incident wasn't an accident either.
so if i get into an argument with someone and totally make the mad to the limit and he goes home and beats his wife to death you are saying i should go to prison with him. all of our actions have outcomes we never predict or imagine are possible and your looking back at there tragedy with hind sight. if you were there you probably would have done the same thing.