Your right in that a more nuanced view of the Indian wars has developed in American cinema. It's a tragic history, that's for sure, but a movie that portrays the Indian or the white man as blameless is of no help. For example, if a story about the Comanche or the Apache did not include a portrayal of cruelty on the part of the tribes then it would be as false as a portrayal of the cavalry as gallant horsemen. It's complex, and I would not blame a Director shying away from such a portrayal. Maybe we were not ready for the truth.
For a book that shows how misunderstanding and cruelty from both sides created a downward spiral of murder, kidnap, rape and ultimately annihilation, then read Empire of the Summer Moon by SC Gwynne is a must read.