I will never understand why they have to keep the bad ones. I worked at a Federal Correctional Facility and the problems there kept getting worse and worse. I reported the problems and they would say "we will look into it". The counselor they hired was out on the streets with the prisoners dealing drugs and doing things they ought not to be doing. The prisoners started to confront me after work with threats because I would not bend the rules for them. After prisoners started to get stabbed and things got worse and worse I left that job. I did what I could but nothing I did made a difference.
The problem is that money is considered good. It does not matter how the money is gotten. A corrupt dishonest person with lots of money is always considered better than a poor honest person without money. That is why there are so many drugs available in jail (gaurds and bribe money). Money is all that matters to some people.