In 1979, William Arens published The Man-Eating Myth, in which he presented his finding that there is no good evidence that cannibalism was socially accepted by anybody, ever, and an hypothesis that such accounts are constructed by society as a way of galvanizing opposition to other societies.
Arens must not have spoken with Michael D. Coe, who wrote that "it is incontrovertible that some of these victims ended up being eaten ritually."
Bernard R. Ortiz de Monetellano writes that only the upper class (in Tenochtitlan, at least), about 25% of the city's population, partook in cannibalism. But with so much else to doubt, I doubt this as well.
Did more than just priests and the upper class eat people in the Aztec Empire? Or is William Arens right that there was never social acceptance of cannibalism in the Aztec Empire?