According to the late Tony Hillerman, who was acclaimed by the Navajo for his accurate portrayal of the Navajo people in his Jim Chee novels, the Hopi referred to the Navajo as "head bashers."
For example.
Our culture has been ignoring the evil and barbaric sides of the aboriginal peoples of the Americas for many years. For example, historians and anthropologists had doubted the existence of the "skull pyramid" of the Aztecs, as reported by the Conquistadors.
http://www.dailymail.co.uk/sciencetech/article-5893933/The-horror-Aztec-tower-skulls-revealed.htmlUntil they have found evidence recently. (As outlined in the article)
Humans are barbaric and evil, all over the world. There is no such thing as the "Noble Savage." That, of course, doesn't stop the oikophobic left from thinking that Western Civilization destroyed all these wonderful, perfect pre-existing cultures.