It's nonsense. He's spinning.

Of COURSE he was fabulating, to provoke the General after hearing how the General spoke of the black soldiers who died thanks to him. The Coggins character totally got what Warren was pulling, but the General did not have Warren's self-control.

She was a sociopathic, stone-cold killer with a "Dead Or Alive" warrant on her head. She was chained to a bounty hunter who told her to keep quiet and not get out of line, and was decent, even courtly, to her for the short stretches when she complied. When she did not comply, which was often, he cracked her in the…

H8 was subtler, grimmer, and smarter than Djano.

Indians killed the real life Hugh. Just not during the part of his life that became the novel and movie.