So I almost stopped reading at "native ecology". You do have a good point about deliberate destruction of what was there, but the American continent wasn't in some kind of pristine natural state before Columbus arrived. The native peoples altered their environment to suit them. What we call corn today came from maize, but maize isn't natural, either. Its closest genetic relation to a natural plant is one with tiny, inedible cobs. It's not clear how they manged to go from that to maize.
Humans alter the environment around them to better suit humans. That doesn't mean we have to be relentlessly destructive, but we always do it in some way. Narratives that native peoples were in some kind of perfect state of nature feeds into noble savage myths, and take away from their humanity.
But focusing on cultural eradication is a very good point.