Got me... I have never personally "needed" one.
I think you have to look at the reality of the police... They are not there to "protect" anything. They are not there to "stop" crime.
They are there to report on crime and to make people who commit crimes end up accountable for their actions.
They arrest people after acts have occurred. That is just the job, plain and simple.
What about the lives that HAVEN'T been taken yet, cops aren't protecting them? Columbine, VT, SB, Pulse, Dallas, Baton Rouge, etc.? Taking out active shooters doesn't "protect anything"?
Ohio cop who took out Nathan Gale (a still-firing murderer of four, including Dimebag) - he didn't stop anything or protect anyone? Ask Vinnie, maybe. Ask Tracie Thompson or Denise Peraza if cops "just arrest people after." What, Farook just got bored?
Another "typo," perhaps? Like with Shizzo?