Yes and no. First, Lonesome Dove is a fabulous book. In real life, it could be more brutal. Blue Duck would not have had sex slaves or sell a women as a sex slave or tortured for fun. Yes, women were raped. Brutally, gang raped. It happened. How much it happened has been debated. Yes, men were known to have their genitals cut off and stuffed in their mouths. This was typically done after they were dead. As for common practice... it certainly was not a gaurantee that if a Kiowa or Commanche killed you, they would do it, but it happened enough where if you came across enough white people killed, you would most likely see that at some point. I dont think it is fair or unfair or racist, but part of a situation most people did not grasp or understand. The Commanche were are warlike tribe. They were nomadic, and could/would move camp sites every few days during the summer season, and many would camp out in Palo Duro Canyon in West Texas in the winter months. So being so mobile is hard on pregnancies. Stealing women and children was one way to help the population grow. It wasn't just white women, they also did take boys, Mexican kids, other Indians. Most of the kids taken would be placed with mothers in the tribe, and more often than not, the new mothers really doted on the kids. Older women, had a much rougher time. Yes, odds are they could/would be raped. This includes stories of women who were many months pregnant. This was not reserved for white women.

It was a brutal time, brutal era. Texans also killed kids, women. The Commanches viewed the Texans as invading their lands, the Texans viewed the Commanches as subhuman.

S.C. Gwynn's Empire of the Summer Moon is a good read about the war between Texans and Commanches. It can be hard to read in places if rape makes you uncomfortable. I set it down a couple times myself.

Haven't many of those things happened when american soldiers go to war?