Above all, it seems to me wrongheaded and dangerous to invoke historical assumptions about environmental practices of native peoples in order to justify treating them fairly. ... By invoking this assumption [i.e., that they were/are better environmental stewards than other peoples or parts of contemporary society] to justify fair treatment of native peoples, we imply that it would be OK to mistreat them if that assumption could be refuted. In fact, the case against mistreating them isn't based on any historical assumption about their environmental practices: it's based on a moral principle, namely, that it is morally wrong for one people to dispossess, subjugate or exterminate another people.
Jared Diamond