You are absolutely correct.
"Sheppard Krech III's book The Ecological Indian sets out to probe the basis and historical validity of the idea that people of native descent are, and always have been, caring towards the environment, a characteristic commonly claimed by or attributed to them. With a series of empirical case studies he investigates whether their ideas and actions were always those of ecologists and conservationists. He finds that the Ecological Indian proposition is of doubtful validity, concluding that, for example, Indians needlessly killed many buffalo, set fires that got out of control, and over-exploited deer and beaver for their skins.
For me, this chapter provides the book's most serious challenge to The Ecological Indian. While Indians had uses for every part of the buffalo, their practice of slaughtering whole herds, at a buffalo jump or in an enclosure, sometimes produced more carcasses than a group could possibly use. As a result, waste occurred. He documents instances of Indians leaving animals to rot, utilising only the cows, or taking only the tongues and the humps. However, the overkilling did not cause the extermination of the species, which only came after non-Indians and Metis hunted them commercially for fresh meat, pemmican and hides. "
Indians were not really ecologically aware until the 19th century.
They were not into any naturally sustainable processes. As their population grew, they would have had the same problem.
Too many humans (even indians) is the problem.