The Aztecs--and I specifically mean Aztecs here and not the Mexica in general--were probably some of the most profligate sacrificers in human history. But outside of them, the pre-Columbian Americans don't seem to be unusually inclined to human sacrifice, especially in comparison to the rest of the world. The difference is that they were first contacted by European society at a time when they still practiced religious beliefs that included human sacrifice while the Europeans had forgotten just how much they had sacrificed humans a millennium earlier.