It shows how the largest amount of the continental territory was inhabited by nomadic tribes, which means that they had no fixed border or civilization, much less rules.
What you are saying here is that if you don't believe in acquisitive property rights, live directly off the land, wander around following the game and the seasons and live in such a was as to not need a structured, legalist authority structure you aren't actually occupying said land and so it's okay to be removed from that land by an invading people whose culture is fixated on acquisition, economic hierarchy, dominance and self-service. Correct?
I would not say that. I am referring to the fact that in most of the continental territory there were no tribe, civilization or people, who, as nomads, did not have a clearly delimited territory. There were many areas that the Europeans conquered without there being an apex of American civilization, that is, without pushing anyone from that place. And that is the main part of the continental territory.
Nor would I say that European culture is fixated on acquisition, perhaps it would be the same for all human culture, if you see the great American civilizations such as the Incas or the Aztecs you could notice how they were also "fixated" on acquisition.