There's no sense in romanticizing and excusing Indian behavior but neither do I see much sense in freaking out over Stone Age pagans acting like Stone Age pagans.
Some specific Indian lore:
In the West, Indians would pretty much always rape women on raids. In the East, they'd pretty much never rape women on raids. The reason was that Eastern Indians, like many peoples around the world, believed menstruation blood had strong magical properties and they did not want to hex themselves by possibly coming into contact with it.
Scalping is a pretty universal custom across the world. Indians became familiar with it - using it frequently - as a consequence of Whites paying bounties for enemy tribes scalps, but they got to liking it so much that it took on a life of its own.
Abduction was common because in many tribes they would adopt the abducted as tribal members. Children are obviously the more likely to actually stay, but it was enough of a feature of Indian society that adults would play along with it too (more than Whites would).
Eastern Indians tended to have matriarchal or at least woman-friendly societies, Western Indians tended to have patriarchal societies. This mostly has to do with Easterners mainly being agriculturalists where women used hoe agriculture and Westerners being mainly hunter-gatherers. Plains Indians often treated women as straight-up chattel. Cherokee women on the other hand were civic leaders and had sexual freedom.
Cannibalism was way more common than people will let on. The Iroquois practiced ritual cannibalism of the organs of loved ones (associated with personality traits of the deceased). Various other Indians, Hurons and Shawnees I think, ate people just to eat people. Karankawas (coastal Texas) were cannibals. Caribs allegedly captured children and fattened them for slaughter. The Mesoamerican world was full of ritualized cannibalism of sacrifices.
Torture was standard. (Torture was also standard in European society at the time.) Comanches were known for being the best torturers, and liked to sand people's feet down to make them raw and make them walk on coals. Iroquois liked burning people, especially Cherokees, alive.
@mindlessobserver I remember us talking about this before, for the benefit of others reading, I disagree with that theory because I don't understand how cannibalism can be explained as filling a necessary nutritional need for any species. It happens in nature, but surely you couldn't have a closed system of people breeding and living lives and dying that requires them to consume nutrients from themselves because they can't get it elsewhere. Flower wars also weren't that large and the Mesoamericans did have access to chihuahuas, seafood and freshwater fish, and various fowl (not chickens) that could be used for meat.
