The thing is there are NO purebred American Indians. All are mixed. A tremendous number (in the tens of millions) of people in this country are part American Indian. Some are a "lot" and others are "some" and "a little".
Not likely any of them owes anybody any apologies, nor should their Congress-critters assume they can speak for them!
The way I read this is that the people still on the reservations are sitting down and negotiating some sort of deal with some white people who feel "white Liberal guilt".
That's a non-starter. The people on the reservations speak only for themselves, not for everybody affected, and they are a minority of the affected anyway.
You are either stupid or ill-informed. There are full blooded Indians all over the place. If you can't find any, go to any reservation in the U.S.
Another point that needs to be made is that from Columbus and Cortez right down to the last battle, European whites had native troops fighting beside them against their "brothers". Indeed the conquest of the Americas would have been impossible without native help. The European powers fighting each other for control of North America all used various tribes against each other and the tribes used the wars to settle old grudges between each other.