Why does La Donna Brave Bull Allard say American Indians have become “invisible” in America?

Banished by the 1830 Indian Removal Act to largely barren reservations in the American West, they have remained invisible to the rest of the country ever since.

This is just generally the reason why Indians might feel invisible, hopefully this helps...

ANSWER: Different tribes had different ways to show that the boys have grown up to a man. It was even different in different cities. In Sparta, the youth had to kill a helot with his bare hands. In some places, they cut the hair of the youth and devote them to God.