d this description:
In spite of myself, I was carried downstairs and tied fast in a chair.

I cried aloud, shaking my head all the while until I felt the cold blades of the scissors against my neck, and heard them gnaw off one of my thick braids. Then I lost my spirit. Since the day I was taken from my mother I had suffered extreme indignities.
How does this firsthand description serve as evidence to support Zitkala-Ša's claim that her people were mistreated?