I'm not in the US, I'm in Australia. My wife & I, we own a house. If you trace back the legal chain of title, eventually it originates in a land grant issued by the colonial Governor of New South Wales in the name of the British monarch – and the British monarch's claim of ownership is based on Captain James Cook claiming the east coast of Australia in 1770 in the name of King George III. But, it wasn't unoccupied land – the indigenous peoples lived here, and they saw the land as theirs. In some other places (such as New Zealand or parts of North America), the British negotiated treaties with the indigenous inhabitants to acquire land from them – the fairness of those treaties is often contested, and the British having acquired the land often ignored and violated the other provisions of the treaty – but, in Australia, there were never any treaties with the indigenous peoples, the British saw them as too uncivilised for that, the British Empire just moved in and took over. So, if legal title based on theft is invalid, and our own legal title ultimately originates in the British Empire's theft of land from the indigenous – does it follow that my wife & I don't actually own this house (or at least not the land it is built on), even though we've paid several hundred thousand dollars for it?

Wherever you are in South America, isn't it the same story? The Europeans (the Spanish or Portuguese or whoever) moved in, stole the land from the indigenous peoples, then divided it up and gave or sold it to European colonists, and it has been on-sold and repeatedly subdivided since – so if land titles founded on theft are invalid, land titles where you are must be just as invalid as those over here.