That was deliberate. The point of this sub-thread is that historical narratives get written and re-written by the victors, and the "right" side of history depends on when you're located in history.

Tecumseh and Sitting Bull have positive legacies because Native Americans are not realistic threats to the United States at this point. They weren't always viewed as such: see for example the (fraudulent) Speech at Tuckabatchee, which indicates how people might've viewed Tecumseh in 1860:

https://en.wikipedia.org/wiki/Tecumseh#Speech_at_Tuckaubatch...