Seems that the Aztecs imposed heavy taxes on the other local Indian tribes, and they took many local tribal members every year for their “sacrifices”. Most of the Indians around Mexico City were farmers, and the Aztecs ruled over them. That’s why they helped Cortez.
It has become fashionable among liberals in recent decades to tell false stories about Cortez. It was impossible for the early Spanish to “enslave” all the Mexican and Central American Indians during the first 200 years, because there weren’t very many Spanish, and there were many more Indians. Anyway, the Spanish men began intermarrying with the Indians immediately. That’s where “Hispanics” come from.
According to Dr. Powell, the American students find it disconcerting when they learn that in the Spanish American lands of Catholicism, a sophisticated European culture flourished, almost from the moment of the Conquest itself. “This included everything from complex municipal and regional government, vast projects for Christianizing (i.e. Europeanization), and protection of even the most savage aborigines, to encouragement and successful establishment of all kinds of schools and universities, hospitals, and the production of scholars and a very respectable literature-a far more exciting and plentiful literature, by the way, than colonial English-America produced. This is to say nothing of economic and commercial activities on the grand scale. Students are invariable surprised to learn that, for all its weakness, the general system and aim was that of ‘ennoblement’ (ennoblecer) rather than destruction.” "Tree of Hate" page 132)