"They did it too!" is a bit of a fourth grade excuse, don't you think?
In a lot of our dealings with the Indians we were an advanced enough society such that we did know better and many people at the time knew it was wrong. Doesn't mean the US is the center of evil in the world or that people shouldn't be proud of this country overall. I'm not proud of every single thing we've done though.
The reality is 90% of the damage to the Indians was due to disease (not caused by "smallpox blankets" or anything deliberate) and it would have happened even if every single contact with Europeans was with the best of intentions.
Disease really doesn't care.
I didn't make the allegation, I raised the question of just ONE of the implications of discovering a pre-ASian human in North America. My reply was to someone who asked why the PC crowd might object to uncovering the true facts of Kennewick man. I raised one possible line of reasoning that those people could be worried about.
I think it would be cool if they confirmed such a discovery, and I don't care who did what to whom in ancient history, as long as no one is doing it today.