I would disagree to a certain extent. "Law enforcement is not your friend" is a good mindset as a citizen. You should never hand them information without a lawyer and you should always push for oversight.

I agree that the "same at it ever was and always will be" attitude isn't great. It's defeatist and I choose not to live my life that way, even if it would be much easier mentally.

I think part of the reason I see this attitude so often is that, especially since 9/11, a large portion of the US population has decided that the police and military are infallible and should be trusted completely, so any large-scale attempt at reform runs into these unwavering supporters (and, in the case of the police, their unions).