Let me state for the record that most terrible things that happen like the railroad disaster happen mostly not through fiendish plans to exterminate innocent people ala Hitler but simple human error/incompetence.
I remember one of my college classes where the leftist professor (who was a so-called expert on American Indian affairs) would drone on in class about how the fed. gov was deliberately trying to exterminate the American Indians. Most of us looked on in either disbelief or boredom during his rants.
So when someone from either the right or the left starts a diatribe about some conspiracy to slaughter people, I immediately get a reading on my inner bullsh*t detector.
The great buffalo hunts were the death of the plains Indians. They had the dual purpose of eliminating the indigenous grass eaters from the land for cattle ranching (buffalo are notoriously hard to handle as livestock), and completely undercutting the food chain/economy of the Plains Indians. Hides were used for everything from housing to clothing, meat was eaten, smoked or jerked, even the bones were used to make tools, hardware, and ornaments.
Without the Buffalo, their society was in trouble, which made it easier to subjugate them.
There is some validity to the argument. We see something similar in the "global Green Movement", where mining and processing of minerals, including petroleum, are under attack. That barrel of oil is the White Man's Buffalo. Without it, our society collapses.