We did not commit genocide on their population. The U.S government was only responsible for around 100,000 deaths, over the course of 100 years. Most of that was during the Indian wars.
The overwhelming majority, 99% of them died of disease. That could be considered mass man slaughter, but it was not intentional.
They AGREED to go on reservations, majority of the time. That land is pretty much theirs to do what they want with. Everyone always bitches about the trail of tears, but they always fail to mention that the Chiefs agreed to leave and go to reservations.