*quality dissection of what "a few bad apples" means in context.
This entire crop is spoiled, tainted by the toxic sludge oozing from the bad apple at the top all the way down.

Are there some police, even most, who would never attack citizens, arrest someone they know to be innocent based on race, or falsify charges? Absolutely. Unfortunately there's a statistical vacuum when it comes to policing themselves. That makes them all accessories after the crime under the law, and as a fact.
The bad apples couldn't represent the police if the police fired them with permanent nationwide records so they can't just move to the next police force after being fired for crimes. Instead they shield and hide those rotting apples behind their blue wall, tainting themselves in the process.

When I see an Apple going bad, I throw it out immediately...I don't wait until it's become slimy and furry, spoiling all my fruit.

Boosting this quality contribution up in the Hot Listing - declared quality by newtboy.