I dont think its contrary at all, the law makes provisions for defending yourself, and where it doesnt, well... your own safety should still be your number one priority, dont let a few laws prevent you from looking out for number 1.
Retrospective punishment is a deterent only, once they have made up their minds to commit the crime it does nothing to protect you, and it doesnt fix your psychological wounds.
Theres no way i can know if the story was exaggerated, like most things in life there was no real proof, and the only people who would know about it is him and the bully. I think everyone in their right mind would be intimidated, those who get aggressive...well then unforutnately its time to step it up a notch until all the fight is gone out of them. Little kids would get nothing but a slap on the wrist if they were even found guilty, i found it to be a good example of an effective threat. The bully leaves you alone, you are not the one who is coming away from the situation the most hurt, its win win.