Yep. The Chickasaw, Choctaw, Cherokee, Seminole, and Muscogee were what was--and still sometimes is--called the Five Civilized Tribes. The Confederacy promised Native sovereignty in the territory that is now Oklahoma, as long as they fought on the side of the South. Given that one of the prerequisites for Civilized Tribe status was, pre-Civil War, acceptance of the chattel slavery of Africans, this would make them horrible bigots if they were held to the same Progressive standard as their white fellows.
A wikipedia article to get you started:
https://en.wikipedia.org/wiki/Five_Civilized_Tribes
I'm going to guess Tom has never heard of the infamous Crow Creek Massacre:
[Link 1] [Link 2]
Or the known archaeological evidence of human sacrifice at Cahokia/Illinois Mounds:
[Link]
As a bonus, have some light reading about warfare and warcrimes among the Natives of the Northeast and Great Lakes regions, circa 1600.
[Link]