We the public, didn't demand it. That is our error.
I am not in favor of painting all of law enforcement as evil, as some people, in their thoughtless unreasonable posts indicate. I'm not going to call it "education by the lowly public". I don't see it that way.
There's a lot of work to do, and Mr Cinque showed us a great, practical model in which to do so. But let's at least acknowledge that is was reactionary (Cinque reacted to bad legislation, and comments by police). We need to equally be proactive, and not wait for this to happen. We should get police chiefs and local elected officials on record; then go from there. As I mentioned, Keith Broaders is doing a heck of a job raising an army of people to keep the sheriffs in check. We need to do the same when we vet candidates.
We aren't. The policemen are. Their actions are simply reported and posted here on FR.