That is a good point. Have you read the book 1491? The author's whole point was that the people living in this part of the world when the Europeans arrived did actively manipulate the environment.

Still, there was a different basic attitude towards Nature. They saw themselves as part of it. Certainly, there is no comparison in the sheer scale of environmental degradation between the two modes of existence.

P.S. Did you ever get around to reading about DDI?