Do you understand now that demanding compensation from Aztec descendants would be highly unjust?
Yes, I agree. I also think it's highly unjust to demand compensation from the Spanish, as I find it unjust for Jews to demand compensation from Poland, Poland to demand compensation from Germany, Libyan or Nubians to demand compensation from Egypt, etc., etc., etc..
This modern-day call for reparations is nothing short of extortion. The oppressors and oppressed of the past are gone. Assigning the sins of the father to the current generation is not only unjust, for the current generation did not commit the oppression, but it's also nearly impossible to distinguish who are the descendants of whom. Generations of mobility, intermingling, and intermarriage have made it moot.
Additionally, the reality is that the current generation are participating members of the culture they live in. A Mexican who is a descendant of an Aztec knows nothing of Aztecan culture and would be lost in it--he is Mexican, he knows Mexican culture because he has lived his life in it. Granted, some may have some kind of romantic idea of living an Aztecan life, but it's merely romantic--if they were ignorant of any Aztecan origin they wouldn't know the difference. It's like if I was to say I'm culturally German (from what I know about my family I'm 75% German ethnicity), although lived my whole life in America--it'd be purely romantic, I'm culturally 100% American.
To speak specifically about the Spanish and Mesoamericans, the Spanish monarchy of today is not the same as it was in the 16th and 17th centuries. It doesn't hold the power today as it did then. It wouldn't be the Spanish crown paying reparations, it would be the Spanish taxpayers. If you consider that just, please explain.
The gold and riches extracted from the Americas by the Spanish aren't hidden away in some account that has been accruing interest for centuries, either. The 10% the conquistadors were obligated to gift the crown was mostly disposed of quickly to pay off debts and fund their wars in Europe.
And, to end this diatribe (as grand and supremely poignant as it is), reparations/compensation/whatereveryawannacallit will not solve any problems or create harmony. It will further divide people and create enmity and discord. It will not bring about justice, accord, and unity.