Unfortunately the police force, like any other "business", has to firstly employ someone on merit.
I was always taught to respect the police, as you need them more than they need you, but in life there are bad apples and these unfortunately only surface when they have been caught out and as you say by then it's too late. They obviously think that under the umbrella of being in the force they would be untouchable and certain cases in the news have proven this to be the case.
No one is born a villain......it's a state of mind, I could have become a right tearaway in my teens {if I so chose} and moved on to become a serial offender and possibly been caught a few times which means I could be now writing this from a prison cell, but I've kept my nose clean..NO I'm far from perfect but the nearest I've ever got to stepping over the line was points on my licence.
As for not showing their faces in the media I have to disagree, plaster their faces all over the media. The wife is always saying on cop shows why are the wrongdoers faces pixelated out, they should be named and shamed, and she's right....Know your enemy!