There were some instances of discrimination. However, there is plenty of blame on both sides. Cultures that do not value private ownership and personal responsibility have a very difficult time coexisting with ones that do. Did you know that sitting bull became an evangelical Christian?
Yes.
You need to look at what is still going on with the SW tribes. McCain just gave away a large chunk of Apache lands to an Australian mining company. It is all about the Benjamins. NE tribes were not sitting on gold, silver, copper, and other precious metal mother loads.