I'm in a strange mood. You have been warned.
There was a really great interview on NPR's Fresh Air earlier this week in which the often violent interactions between white settlers and the Comanche is discussed. It's well worth a listen.
One of the issues discussed early in the interview is the way in which Native American cultures have been "whitewashed" in the last several decades, primarily in response to the earlier tendency to portray all Native American peoples as savages. The impulse is an understandable one, but also, I think, a mistaken one. It tends both to reduce our actual understanding of both history and human behavior, and it also leads to the sort of bizarre history in which the actions of nobody make any sense.
It has also had the weird effect of further separating groups of people. One of the points that is made during the interview is that the violent raids committed by the Comanche were not really any different from violent raids committed by tribally-organized peoples of Europe, Asia, or Africa. I would go a step further and argue that modern warfare is simply an extension of these old raids, and often engaged in for the same reasons (resource procurement, political pressure, ideological differences, etc.). However, the perception of these types of raids has led to people believing that there are more significant differences between groups of people than there really is.
Edit: As a commenter pointed out, it should also be kept in mind that it was not unknown for the settlers to commit similar raids against the native peoples. The reasons were similar: revenge, resource procurement, and wanting to frighten "the enemy."
In the 19th and early 20th century century, when these raids were occurring, they were portrayed as terrifying events, as a violent and beastial people on a rampage. Of course, little mention was generally made of the fact that the settlement of southwestern territories and the great plains impacted the resource base, often making raiding the best way to both push back settlers (and thus restore the resource base) and to make up for losses caused by the settlers. Nonetheless, the brutality of the raids often left the settlers to portray the raiders as something other than, and sometimes less than, fully human. This view continued to inform popular portrayals of Native Americans up through the 1960s and 1970s, and enforced an "us and them" mentality amongst much of the U.S. population, long after armed and violent conflict was decades gone.
Since the 1960s and 70s, the tendency has been to romanticize Native Americans, and the raids are usually justified and played down, if not entirely forgotten. I have met many people, including a number of primary and secondary school teachers, who subscribe to the notion that there was no warfare in the Americas prior to the arrival of Europeans. So, now it's Europeans who are cast as the bad guys, but it's basically just a pendulum swing over to the reverse "Us vs. Them."
The reality is that the raids were part of a spectrum of human behavior that all of us are capable of. They were brutal, involving killing, torture, gang rape, and kidnapping. And anyone familiar with history will know that the Romans and Greeks documented their own armies engaging in similar, if more organized, behaviors. As did the Vikings. As did the Normans. As did the Celts. As did the people of every region of every populated continent.
The tendency to forget or ignore this type of violence on the part of some groups of people is part of a modern political reworking of history, just as the tendency to play it up and ignore the causes during the 19th century was part of a political reworking of current events. It is understandable, but should, nonetheless, be viewed suspiciously. Associating notions of perfection or nirvana with periods in the past or with specific cultures does little other than put those people or times outside of human experience and provide a false view of our nature. There was no perfect culture or golden age of humanity. We are all both magnificent and frail.