An important distinction to make here is that the indigenous people of North America did not own the land themselves before the Europeans came, they coexisted with the land and held spiritual connections with it. One reason why they thought it was a good idea to sign the land over in those treaties is because they thought the notion of any persons "owning" land was ridiculous - no one could own land since the Earth was it's own free spirit

(Not an expert, so please correct me if I'm wrong)