Raiders are not Indians. Indians were just people at odds with the early American government, and most people at our point in time do not like the decisions made by the American government at that point in time. The Indians primarily resorted to violence because they were repeatedly cheated, given some cheap beads or some chickens in exchange for a lot of land.

Raiders are the guys that did 9/11/01, the guys that crashed planes into two skyscrapers and the Pentagon, murdering 3000 people. They are monstrous fuckwads who believe that G-d is a genocidal asshole who will give them 72 virgins if they kill as many innocent people as they can in the most barbaric way possible. That's not Indians.

The player is whoever you decide he is. When you're being shot at, you return fire even if you're a good person. If you choose to lead a good-aligned faction and protect weak but innocent people, you aren't a monster for putting down people who try to murder those weak but innocent people. If you really are making the moral equivalency of a good person shooting some thug trying to kill innocent people to the thug he shot, then that says something about either you not paying attention in school or your teachers in school being complete idiots.