why don't lawful overseers check and correct awful overseers?

theatlantic |  What I found alarming was the fact that those other cops didn't stop or report the bad apples.

In fact, even after higher-ranking officers were alerted to Sampson's experience, that did not put an end to his repeated jailing. Neither a public defender nor a judge was able to spot or stop this miscarriage of justice either. No one inside the system successfully exposed or remedied the abusive situation. Things only changed for Sampson when the store owner got video evidence and took it to the media. And even then, the egregious misbehavior of the police officers went unpunished.

Most of the perpetrators are still on the job.

What do police officers make of this story? How do they explain the fact that such abusive behavior continued for so long? What do they regard as an appropriate punishment? What would they suggest to guard against similar abuses elsewhere? What would they do if they encountered fellow officers treating a man this way? I don't mean to suggest that police are of one mind about this or any other controversy, or that Miami Gardens reflects how police behave everywhere. But when the public reads or listens to stories that document egregious police abuses, it is rare to encounter any members of the police community who express alarm, or champion reforms, or denounce the bad apples, or articulate why they have a different view than the conventional wisdom.  

If you're a police officer, maybe no one asked for your opinion on a case like this before. I invite any of your thoughts.