Like most issues, this falls into the realm of greys, though either side would like it to be seen as black and white.
Native tribal leaders are about as corrupt as polititians. There are good reserves, but in my experience they are not the majority. The governments are fine with this as well. Handling of native issues is murky and has little political value. Given a long enough time line, the native population living on reserves will dwindle and be absorbed into the US and Canada.
The european settlers did annex the land as the native population were unfamiliar with politics. Had they been hostile and tried to prevent the settling, they would have been wiped out by a superior military power.
Since those days, the original settlers from England, France and Spain no longer hold any political power over the Americas. The lands are filled with people from all cultures that had nothing to do with the original native issues.
Was there an injustice? Yes, but those wronged are long gone. The political powers are gone. Some wrongs cannot be corrected.
More land will not be taken and given native communities except under the most rare of circumstances.