Ok, I was married to a cop for 15 years. I heard all the bragging. I could tell you stories, maybe I will sometime. He really did want to make a difference, as well as did others I knew. Problem was, after "x" number of years they get cynical, happens to the best of them. Pretty soon they don't trust anyone. And I mean anyone. They think everyone lies. They don't trust that the system will work for them to keep someone they arrest behind bars, so they may (not all) want to assist the perception or make the case tighter with a little help.
Then there are the guys (and some women) who love the chase, love the high from fighting, love the power. We used to call it the Wyatt Earp syndrom. We knew one guy, short guy, really arrogant cop, on his off duty time he walked around with his weapon tucked into the front of his pants behind the belt. We used to pray it would go off.
My ex was not and is not a dirty cop. What he was is an abusive bastard. Controlling. Want to know why cops are on the top 10 list of professions prone to divorce? There is a reason for it. Namely all of what I mentioned above. During the time we were married I was a witness. The elders used to just about lick his boots trying to kiss up and recruit him. He wasn't buying. Made it a bit harder when I would go to them and tell them about the abuse. They reminded me how tough single mothers have it and that I would still be legally bound. Once after telling my elder dad about the abuse he asked me what I did to deserve it.
So, I don't trust cops as far as I can throw them. Because they are not very well educated, they work long hours, all they have to do is say they are afraid and they are cleared from deadly violence no matter if you are a 70 year old woman or a 16 year old kid. And for every one that is still wet behind the ears and wants to make a difference there are 3 or more that are on a power trip and like kicking kids and small dogs.
Ada