I don’t think they were trying to downplay the severity. I think they were just pointing out in a snarky way that there were survivors, and thus, we can ask their descendants these questions.
It’s the control. If one Native tribe still controlled the ancestral grounds of another tribe, then you probably would have some people calling that out… but they don’t. The US government has ALL the control, every tribe within US territory, and all of their land, is at the governments mercy.