Cops are not the only people who have to deal with other people, they're just the only people allowed to use a stick, an electric shock device, and a gun at their discretion in order to do it. It's a less dangerous job that housepainting, driving a cab, or working in a convenience store.
Ridiculous. You don't expect an abuser or a drunk at every single house you paint; every customer in your cab's back seat isn't belligerent. Again, ride along with a cop some day, it will change your view forever.