In the article, Means says:

A lopsided emphasis on humans by humans--the Europeans' arrogance of acting as though they were beyond the nature of all related things--can only result in a total disharmony and a readjustment which cuts arrogant humans down to size, gives them a taste of that reality beyond their grasp or control and restores the harmony. There is no need for a revolutionary theory to bring this about; it's beyond human control.

and later:

Mother Earth has been abused, the powers have been abused, and this cannot go on forever. No theory can alter that simple fact. Mother Earth will retaliate, the whole environment will retaliate, and the abusers will be eliminated. Things come full circle, back to where they started. That's revolution. And that's a prophecy of my people, of the Hopi people and of other correct peoples.

So to answer that question, it's not defeatist per se. It's utopian.

I'm not well versed in the anthropology of China for example so i can't really address that part but the main point of the article imo - and it makes sense if you read up about indigenous struggle in the americas - is that authoritarian Marxism is incompatible with their cultural heritage as it looks at nature as a resource the same way capitalism does.