I think what's going on is certain anti police websites have been dumping their articles here on RPF. These scary incidental accounts paint a stark picture, but they don't describe the average cop any more than the stories about crazy survivalists describe the average libertarian (perhaps the average Alex Jones listener though

). Keep in mind that a lot of the abuse you hear about takes place on the federal level. Local cops live in the town they work in, a lot of times that's also where they were born and raised. They're just looking for clean streets.
It varies from place to place, I'm sure the cops in the city are likely not going to have quite the same tenor or demeanor as the cops in suburbia. But that's what you'd expect right? As far as comparing cops in general to the SS... come on man. That's just crazy talk and you know it.
For the record, if we really did have an anarcho-capitalist, totally libertarian society, do you really think there wouldn't be any police? REALLY??? We've had officers walking the beat since Roman times, heck even before that. It's one of the hallmarks of civilization.