Not true. The offending officer and the boss who supports him become the dicks.
I've worked for more than one department and have "dropped the dime" before, as have many. I'm not interested in defending someone elses stupidity at the risk of losing my job.
The reason for the good apples not getting rid of the bad apples is that there are bad apples at top too. You change a culture through new blood. Some PDs have never had a problem. Others have turned things around, while some aren't going a thing.
People are always saying dumb stuff like "I once knew this cop and he was a big baddy. Therefore every cop from every part of the cuntry is a big baddy too!"
Before I became a LEO I had a few run-ins with some asshole cops. Luckily for me I realised that, like any other job, you get good ones and the bad ones. I've been around long enough to know that the bad ones don't last very long.