People always talk about the oppression as ancient history, but it has been perpetual for many groups, not just limited to indigenous. Allotment ran until 1934, giving away native lands. After that they moved to Termination, where they tried to dissolve reservations and negate treaties.
Not even bothering to work out the logic, is he. If he did, he wouldn't have any right to be angry, and he really, really wants to be angry. Imagine some foreign government gracefully granting you the recognized right to fish in your own damn house.