Let me spell it out for you.

We wanted to expand into Indian Territory. We wanted their land for our puposes.

The Indians resisted.

We could not defeat them militarily, so we went after their food and and raw material supply, the buffalo.

At first we just killed the bison indiscriminately, then we developed an industry that got wealthy off the hides, leaving the rest of the carcass to rot. This way we dind't have to pay professional hunters like Cody to kill the beasts, we let the hide trade itself develop and finance a market and an industry to do the job for us, while workers took the risks, both financial and physical. The Indians, after all, knew exactly what we were doing to them and they resisted.

Of course, I suppose you just see it as "market forces at work". I concede we did not set up a committee of evil capitalists to mastermind this scheme, but it worked out excatly the same as if we had. A culture was exterminated--the definition of genocide, because we wanted their land for our farms and our railroads, and our hunger for minerals.

Or are you trying to imply that the Indians' management of the range to maximize buffalo production in the pre-horse era justifies our activities because we were just a more efficient way of harvesting the resource.