I note that there are no "days" for Jews, Irish, Poles, Chinese, Vietnamese, inter al.. I, personally, am not alarmed by this dearth. Certainly Columbus initiated a frenzy of greed and cruelty perhaps unmatched until the 20th century. On the other hand, anyone who believes that native Americans themselves were completely innocent of aggressiveness and cruelty needs to read more and better history. We are all--and always have been—“in this together.” The definition of what is wrong with us is not limited to particular periods or nationalities. It is is coextensive with our very species.
Someone from another world would have to infer that our main instincts are to reproduce and to murder each other, but not in that order. The inference would be valid.
I conclude this not from my acquaintance with individual people, most of whom are not greedy or murderous. Rather, I conclude this from the mass of people, their history of one war after another and my acquaintance with our historical "heroes," mass murderers like Alexander, Caesar, Napoleon, and Grant. These, and so many others, did not wage war for principle; they waged it for gain or--worse still--"glory." A tiny percentage of all wars were waged out of self-defense.