Assuming a non-Singularity future where all the second-order witnesses have died, one would not expect many people to go and watch video of 20th-century atrocities. I mean, first-hand accounts of the Spanish Inquisition and the genocide of the Americas exist. How much of them have you read?

(In high school, we read a few excerpts at most; I did read this book in college, thanks to its Great Books focus. Of course, I read plenty in high school about slavery, but that's because the Civil War is still tied to current cultural divides in the U.S.)