Perhaps the core of the problem is not that the police force is institutionally racist, but much deeper. The police force merely reflects society as a whole, and in a competitive capitalist society it is absolutely bound to discriminate between different sub-cultures within society in order to protect and and promote the social order (hierarchy).

As a film this works very well, focusing on the individual experience and conflicts, both internal and external, that arise. Clearly there is a sense in which he is a traitor to his community, but whilst this is shown the implications are not really explored, the film preferring to focus on the problems with the police. 

In this respect this is the weakest film of the set, Mangrove, Wheatle, and Education all show the protagonists involved in finding solutions to their on problems (and Lovers Rock is a bit of an outlier)