"Why should a city of 90% black have 90% black cops?" To relate the people. Otherwise, you end up with white cop killing another black kid....and when it happens time after another....people have problem with it. It appears to the other side as if they are occupied or they are in an apartheid... If you don't relate the people, if people don't respect you for the good work you do, if people are forced to respect the authority as a result of fear, the authority itself becomes a totalitarian, occupying force.
In Ferguson, you can thank to black Chief of police that was appointed the day after the killing of Michael Brown, IMO, saved lives and more property damage. In all previous black riots there were many people got killed, with much looting and property damage. This time we got lucky, the people in Missouri was smart enough to appoint that guy who was able to relate and calm the anger down, keep it under control.
"Maybe the white officers are just more qualified to be police officers... " Well maybe the liberals are much smarter than conservatives and you should listen them. (BTW, this is a proven fact after many studies.)
"Do you not see the problem with that???" Ohh YES! I see a huge problem. A problem that has been holding this country back. A group of people who does not believe in science, nor facts nor truth are making decisions for the country. They are called Republicans and they are the problem for this country. They have chosen to split this country in ethnic lines, religion or anything you can name it. They have made 'failing of this country' their number one goal.