Great movie but the author and/or director completely forgot or ignored the plight and treatment native Americans from them caste hypothesis/equation, Seriously!? Why?

I would think Native Americans should have given some sort acknowledgment from origin standpoint as they were first to be "casted" prior to African Americans.

I haven't read the book, but the movie does feel like abrupt in trying to connect and transition amongst different story lines or historical situations.

Then summarization in the end is just beautifully done. But movies felt too dense and compact in terms of content as the authors personal life events and challenges were being tried to intertwined hit socially and racial complexities.