There are plenty of photographs of stuff we did against the natives, sure. I don’t believe for two seconds that the average high school educated American has ever seen them. We don’t go out of our way to teach that shit.

I suspect it very much depends on your era and region of schooling. I was not exactly attending a top school or in top classes, and the most infamous atrocities of the Indian Wars were covered in US History in high school. But I was in a blue state.