Then, also, these cops you talk about who do behave well do not seem inclined to do anything to improve the situation. Quite the opposite. They close ranks and defend the worst among them.
How good is that sort of behavior? In my opinion that makes them accessories. Perhaps not equally guilty, but their hands are far from clean.
I think this is a situation that has to be addressed, but I'm not sure how. So maybe examine why cops either cover or turn a blind eye to the transgressions of their fellow officers. I think it might be a little simplistic to just label them complicit and blame it all on police culture. Let me explain before you start yelling....
No one likes a tattle-tale. That's ingrained in us from grade school up. The kid who tells on another kid is seen in as much (or more) of a negative light than the kid who was doing something wrong.
The movie "Scent of a Woman" comes to mind. Al Pacino's speech begins with "But not a snitch!" and then goes on to talk about integrity. It's a bit more complex than that, but being a "snitch" is not associated with integrity. At least not on the surface. (I know, there's more to it in the movie.)
In other careers, most people don't want to inform on their colleagues either, for reasons that, in my opinion, go back to grade school. No one wants to be the outsider in the group. And the group doesn't trust the person who rats on Joe, even if the group doesn't like or trust Joe or the things Joe does either. Of course, stealing office supplies, snooping through the Boss's desk, or even faking numbers in a time report are of a different magnitude than what we are talking about here. But still, it applies.
Perhaps, more so, actually. If you're a snitch at the office, no one talks to you at the water cooler and you aren't included in lunch plans. And yes, that sucks and leads people to find new jobs. (It's probably why harassment is often not reported.) But for a police officer or a soldier, you might find yourself in situations where you are depending on people who don't trust you and who, as a result of reciprocity, you don't trust either.
I didn't write the above to in any way excuse the officers who don't report their fellows. I often rant to my wife that other officers present are accomplices. In my mind, the correct thing to do, having just witnessed another officer commit a crime, is to cuff him and put him in the back of the car like any other criminal. (I also recognize that this isn't particularly practical.)
But if you want to address the silence of other officers, you have to recognize where it comes from and I don't think it's unique to police culture.
In theory, body cameras should help because they would not only record the crime, but make it so that witnessing officers have little choice but to speak up or at least speak the truth when confronted.