Americans onto reservations. Could even start when the Federal government started breaking its treaties. The whole "when do we start" argument as a reason against doing any actions is disingenuous when there are concrete instances of oppression littered throughout the short history of the United States. 

Absolutely private charity ideally would be the primary source of help. But private charity is underprovided for various reasons, include the free-rider problem. We can argue whether having a inefficient government provide assistance where private charity fails is better than providing no charity at all, but I believe from a societal standpoint, it's symbolically important that a government "for the people" play the role of charity of last resort.