I think that is a very understated aspect of the current perspective regarding polcie brutality, at least in the states. We grow up learning the ideological aspect of who the police are and what function they are supposed to serve in our society and as a result, they get attributed an authority figure status that associated with pure ideology.
The fact of the matter is that policemen go through a minimal amount of training and are immediately integrated into a social system that is cut off from the rest of the world where they learn to take their social cues from other police officers. They then learn loyalty to this social subset and all of the paranoia regarding criminal offenders gets primary reference in their working memories - they essentially view the world as police and not police. They are also just regular people who are subject to the same temptations as regular people and invariably find themselves committing numerous violations with a very strong basis for rationalization/justification - a basis that everyone else doesn't get.
Studying Black History was amazing in that it allotted me an opportunity to reflect on the historical lack of economic opportunity given to the larger Black community and as a result, offenses such as drugs, prostitution and theft were almost necessary endeavors for economic achievement yet they did not represent a majority of occurrences. In fact, employed white people do drugs on a level that is similar if not greater than the Black community yet the number of arrests for each demographic is incredibly disproportionate - which means that there is kind of an institutionalized racism that is being employed. From a sociological perspective and dismissive of the popular ideology regarding police, it is a huge mess that is being almost completely ignored.
If these types of narratives were more prominent and acceptable throughout our society then we might have an opportunity for immediate progress but there is way more motivation to deny and cover up then there is to do this...and that is likely not something that is going to happen for a while if ever. I keep thinking that the internet has opened up our society to these types of communications but in order for it to have a bureaucratic effect we likely need to see a new generation represented in higher offices...
If this seems kind of discombobulated then my apologies...there are a few points scrunched up in here that likely deserve their own expanded posts for clarity...