Again you are focusing on those that do human sacrifices but you doesn’t make a mention about those that don’t. This form a bias that makes it apear that human sacrifice is common when it is not. Very similar thing happens to plane crashes. Though it happen far less often than car crashes, media reporting which focuses more on plane crashes (because it is dramatic) make it appear that it happens often. People fear plane crashes while they gladly ride a car when they are more likely to die in the car than in the plane.
Hmmm. There is very little known about why Aztecs and Mayans do human sacrifices. Though I wonder why human sacrifice should power a demon conjuring. How does it work? Also, these sacrifices are for their Gods.