This analogy falls apart some since there was never a concept of land ownership (to my knowledge) amongst the various North American tribes, so there wouldn't h

This analogy falls apart some since there was never a concept of land ownership (to my knowledge) amongst the various North American tribes, so there wouldn't have been "fenced-land" semi-permanent dwellings to take over to begin with. Also, not all of them were welcoming in the romanticized way you present and many of them were very brutal to rival indigenous groups. In short, it's a little more complicated than that. Certainly there was much evil committed towards indigenous peoples in many places, though. However, the Aztecs weren't very nice to their neighbors and the fact that they were betrayed by the Spanish seemed like an apt comeuppance for a group led by bloodthirsty warmongering maniacs.