Established historic fact should not be tampered with in movies based on actual history. The parts that are dramatized should responsibly be a good interpretation of how they would've happened.
British historic dramas are pretty good at that (ex: The King's Speech).
The Ferguson crazies and their enablers are creating a world view for themselves that all whites in positions of authority are the enemy. If this movie re-enforces that stereotype, it's not only bad history, it's dangerous.
JMHO
Ever heard of Shakespeare? He wrote History plays that were about as accurate as a soap opera.