The Nez Perce signed a treaty at the wall walla council in which they 1were given Full control of their reservation lands

2 Had to share reservation lands with other tribes

3Turn over most of their land but could still hunt and fish on it

4Retain the right to own most of their ancestral land​

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.