What am I?

You teach children from birth that I am the bogeyman.
You accuse me of being too soft on the young... until its your child.
You know the road rules but when you break one, you are not to blame.
You see it as part of my job if I get beaten or shot; but if I hit back you call it brutality.
You complain that I earn too much, but expect me to be available twenty-four hours a day.
It would not enter your mind to tell your dentist or doctor how to perform, yet you tell me how to do my job.
You complain that something has to be done about crime but refuse to be a witness or become involved.

But you forget your possessions, your family, and your life are in the hands of my colleagues and me. I am a Cop!