Note on nomenclature: Either American Indian or Native American is generally accepted by natives, but we generally use the shorthand term Indian. I will do so here just because it's so much easier than typing either of those phrases.
How many Hollywood movies do you know of that are about or prominently feature Indians? There are really plenty, a few of which I'll name here. Most recently there was Pathfinder. Not long ago, there was Windtalkers. Longer ago there was Dances with Wolves or Last of the Mohicans. And further in the past there were Little Big Man and A Man Named Horse. This page has a pretty decent list of films like this.
Don't get me wrong, I'm not about to start bashing these films. Well, maybe Windtalkers. John Woo is hit-or-miss with me and I really thought that movie was kind of silly, but I liked the others well enough. Anyway, back to my point. In respective order, here are the stars of those films: Karl Urban, Nicolas Cage, Kevin Costner, Daniel Day-Lewis, Dustin Hoffman, and Richard Harris. See a pattern yet? If not, let me help you. Urban is from New Zealand while Daniel Day-Lewis and Richard Harris are English. Nicolas Cage is Italian-American, so unless there's some incidental contact through Hoffman and Costner, none of the leads of those films are Indian. That's not to say that Indians don't play prominent roles in those films, or that they're disrespectful of Indian people. Well, let me say they're not necessarily trying to be disrespectful, although a certain degree of historical inaccuracy is to be expected.
But seriously, once in a while I want to see a big historical epic about Indians with Indian actors as leads. You do see this from time to time, although more often on TV than a big screen movie. You might recognize these three guys:
From top to bottom, that's Russell Means, Wes Studi, and Adam Beach. You can see all these guys in lots of films where it matters that they're Indians, and many where it doesn't. But you won't see them as the lead in any major Hollywood film. Wes Studi was in Heat, but not really a main character. Adam Beach was in Flags of our Fathers, although mainly because that role required an Indian, and Russell Means is pretty much the go-to guy for an Elder.
I realize this is a problem for all the minorities in America. I go to the Asian Film Festival of Dallas every year and I hear the Asian-American actors they invite to speak talking about how difficult it is to find roles for Asian-Americans in Hollywood films. Believe it or not, Harold and Kumar Go to White Castle was a big deal. But there's not a film like that for Indians. I think the closest we got was with Lou Diamond Phillips in Renegades (which co-starred Kiefer Sutherland) because he claims to be an 1/8th Cherokee. Or perhaps Thunderheart with Val Kilmer, since his stepfather is Hopi or something.
Why are we treated this way? It's not insulting that we don't have actors put in films, it's insulting that the films that are about us don't star Indians!