“buying land doesn’t really mean much.” Tell that to the Palestinians who got upset when Jews moved into the land they sold to them. One thing it definitely means is the new owners might move in.
American settlers did obtain their land legally too. What’s your point? That to begin with, without us legally obtaining that land you wouldn’t have electricity. You wouldn’t have airplanes. You wouldn’t have a cell phone.
We didn’t murder millions of natives. Smallpox killed millions.