My wife and I raise Angus beef cattle and we have experienced calves die in our arms trying to save them. It is inexplicable why some calves do fine and some don't. But once the mother rejects them, it is almost certain they will die.
It is nature's way.
I lived through middle school and HS in the deep woods of extreme northern California. Nature does not F around.
You are correct. So often when humans try to intervene, the situation worsens. I believe the bison calf should have been left along.
But I find it the ultimate irony that the National Park Service, who would condemn a tourist for upsetting the cycle of nature plays around with nature all the time, like introducing super predator wolves in Yellowstone and other parks and those wolves in turn decimate the ungulate (hoofed animals) population in those areas. Elk, deer, moose and antelope have all seen a precipitous decline in population in the mountain west states.
The NPS should live by the same rules they would impose on the rest of us.