This analogy is naïve. There is plenty of evidence of extermination behavior among early native Americans. In more recent times, the Anasazi were especially feared by their neighbors for the horrors they'd inflict.
Did the Anasazi exterminate nearly everyone on an entire continent, then march the remainder into reservations where it remained illegal for them to openly practice their religion until 40 years ago, and did they kidnap people's children and send them to boarding schools to be indoctrinated against their own culture, abuse and torture them, and bury them in mass graves?
No. It's not even in the same ballpark.
And one doesn't justify the other. If I break into your house, kill your family and steal everything not nailed down, including your youngest kid who I raise as my own, and the bones of your dead aunt that I put in a window display, I can't justify that by pointing out that you got into a fight with a kid in high school one time and once stole a pair of sunglasses from the Wal-Mart.