That's why police exist in the first place (if you're not thinking too cynically about it). The main job of police is to reduce vigilante justice and mob violen

That's why police exist in the first place (if you're not thinking too cynically about it). The main job of police is to reduce vigilante justice and mob violence. If the police don't shut up someone's dog, convict a blatant rapist, or punish a murderer, expect the people to take it into their own hands.