"You're thinking of the wrong natives, that was over in Mexico and Peru. Columbus landed on Hispaniola, which had fairly primitive agricultural and hunter tribes."
For what it is worth, according to Columbus' personal journals, Columbus had no reason to rape and murder because he was often greeted as a 'god' when he went ashore. And, every man he left behind on his first (?) journey was murdered by the "primitive"s.
As for slavery, we are in no position to scrutinize the practice as "enlightened" people; slavery happened, it is a fact, it cannot be historically used to denigrate a persons character. (Slavery was even a practice between differing Indian tribes.)
Quick, somebody name one race that hasn't, at some point in history, been enslaved by someone else.