I'm not sure if this is fair. Of course there will be reprehensible individuals, but that is true of any profession or group.
If you read blogs like Inspector Gadget, there are a lot of comments from people who at least claim to be serving and former police officers. The overwhelming impression that one gets from these is that most coppers hate this kind of thing, but are often required to do it.
I don't think this is a problem with the rank and file, but rather with senior officers and politicians.