No one’s going to give a fuck who bullied you once you start shooting mate.

Once I start shooting I wouldn't care who thinks what, no?

now, there may be factors involved that drove the person to murder, but they don’t justify the murder. And they certainly don’t get to blame the MURDER VICTIM, or their parents, for murder.

A bully is not a victim and gets what's coming to them. Same as killing in self-defense.

Anyway, the mechanism I've described improves humanity, because bullies want to bully and don't want to die, whether their victim then goes to jail or not.

A dead person or a person in jail doesn't poison the society, neither does someone who killed another in self-defense or under mental duress consciously inflicted by that person. A bully who is not dead and not in jail does poison it quite a lot.