This instance does not sound like an insane cop that needed to be dealt with....it sounds like the guy with the shotgun was the one that was insane.
You are right in this instance, but I don't think that we can make that a blanket statement about law enforcement anymore. A lot of these small town cops have gone from being the neighborhood protector to being some sort of paramilitary thug thinking he is on an episode of cops. Freemansburg cops are notorious for just sitting in bar parking lots to hit DUI's.
The most consistently professional cops in PA are the State Police. No matter the situation I have seen them in, they stay calm and try to handle the situation as efficiently as possible. They also don't go out of their way to bust people for revenue enhancement.