Still, if I were looking to pre-contact America for life lessons, I would look at some more northerly tribes, first. But we don't know as much about what they thought.
The documented death rate of the inquisitions is on the order of 4500 people over 400 years [1]. That’s a rate of 11 people per year.
Aztec sacrifice estimates are on the scale of 20,000 to 250,000 per year. [2]
In actual fact, the Aztecs are in a far worse light than the Dominicans and Franciscans. The Nazi comparison is valid. There’s no society on earth that would end innocent life on that scale for another 500 years.
[1]: https://history.stackexchange.com/questions/39443/what-was-t...
[2]: https://en.wikipedia.org/wiki/Human_sacrifice_in_Aztec_cultu...
The Albigensians alone numbered more than 4500.
IMHO people / cultures / civilizations aren't all bad or all good, there's always something to learn about them.
If people / cultures / civilizations vary in the level of goodness and badness in them then it follows that there should be a distribution of societies that are significantly more good than bad, societies that are average, and societies that are significantly more bad than good.
If a society is significantly more bad than good it can be true that you could still find something good in them but it becomes questionable if it is worth an individual to study the society to extract this good part from all the bad.
Thus I would conclude that it might not be really worthwhile to learn anything from the Aztecs.
One historian I read said if Cortez had shown up 50-100 years later they probably would have ended up facing those those guys first instead of the Aztecs and had a really bad time.
Good and bad are time and culture specific. In 50 years, many things that we do everyday now will be "bad" and many things that we see as "bad" will be "good."
Slavery? Genocide? Plunder? Rape? Religious violence? Slaughter of peoples they considered inferior? The "civilized" Christian cultures of the time did everything the Aztecs did, minus the human sacrifice.
One is just more alien to Western culture than the other, so it seems more viscerally evil, and their means differ but their nature is the same.
The crusades were armies raised in response to the Muslim invasions of Christian countries. Motivations varied between religious (defense of the Christians being oppressed) to political (I want a kingdom to rule over) [1].
[1]: https://history.stackexchange.com/questions/7915/are-there-a...