Police in uniform abusing their authority is not news. In fact, it has happened since the history of time. On of the things that all men yearn for, whether consciously or subconsciously, is the desire to be above others. This drive causes men to produce more testosterone and to attempt to improve themselves physically.
Society has given them a chance to do this, via resources. Money equals power. However, there is another way. Becoming a police officer gives people who are normally do not have authority, power over others. This is obviously very easy to abuse.