I don't think so. How many genocides can you think of on the scale of the Native American genocide? Such events seem rare to me.
That was, what, a 95% extermination? Native Americans probably committed 100% exterminations e.g. https://en.wikipedia.org/wiki/Dorset_culture
History was full of violence.
Em. First, numbers of "native ancestry" are almost all self-reported which has more to do with self-identified culture than genetic ancestry.
Second, trying to argue through the use current numbers of native ancestry is nonsensical given the US has been an outlier in terms of immigration for a very long time making it impossible to compare against. For goodness sake, around a tenth of the population has been foreign born for the better part of two centuries which has had a dramatic effect on ancestry (both genetic and self-reported).