The Aztec, while the greatest civilization on the continent before Columbus was notoriously cruel and bloodthirsty.
In the 12th and 13th century, their practice of human sacrifice was limited to an occasional choice maiden or young man from their own tribe. By the 14th century, it expanded to include that demographic from other tribes to substitute for their own.
As you can imagine, the other tribes did not take kindly to this practice, so by the 15th century, it expanded to entire villages of men, women and children. Many tribes were wiped out by the Aztec, others faced near extinction. It was only the arrival of the Spaniards and the fall of the Aztec empire early in the 15th century which saved what little was left of them.
Darn right. That's why Cortez was able to enlist thousands of Indian tribesmen to help him and his 500 men and 150 horses in taking down Montezuma and the Aztecs.
I think I read that the Aztecs had only been in Mexico City about 75 years when Cortez landed, so memories of the Aztecs' unlovely acquisition and management procedures were quite vivid.