I know this is hard for you guys to believe, even though I am a retired LEO, I know your pain. I've had run ins with the type of cops, that you describe, both before I became a LEO, and while I was a LEO. Usually, if you ask around, even their fellow officers will tell you that particular guy is an "@" aka "A - circle".
So he would have been a "@", whether he was a cop or not. But, you have to realize, that the guys you are describing are the exception not the norm. Most of us are decent individuals, and usually we are the ones that give a lot of our time to the community (scout leaders, LL, Pop Warner coaches, etc.). What I'm trying to tell you guys is hate the individual "@", not the guys that happen to be wearing the uniform.
If you feel strongly about the issue, stand your ground, politely, but firmly.
If you have a problem with a particular individual behaving in what you feel is an unprofessional manner, try to remember/document what he did, then write a letter nice letter to the Chief of Police explaining the situation/acts. Most large urban police departments, have a civilian complaint board. You might not get the situation resolved to your satisfaction but, if that particular officer gets enough complaints, eventually the municipality will have to do something, because it will cost them lots of money to resolve lawsuits involving that particular officer.