When's the last time you read about a police officer going to jail for shooting the wrong person or shooting a person that didn't need such force? What about tazars which since it's "non-lethal" they seem to feel free to use willy nilly? I would not call this holding police to a higher standard at all.
I personally know of several instances where the police use of a tazer has saved a life. Like a recent case of a man holding a knife to a woman's neck. Methinks you paint with too broad a brush.