Because they typically do especially if the school is in a bad neighborhood or covers more than one jurisdiction. Chicago is a shit hole and I am sure there are some poorly patrolled areas but what can you expect when the protest even armed men being shot? Facts down matter their is just the cause and a deeply felt TRUTH of righteous victimhood.
I have two sons and if either wanted to join the police I would do everything I could to talk them out of it. It has become a shit and thankless job where even if you are in right you can publicly defamed and if you do make a wrong split second decision you can go to prison.