I'll be honest, I've been studying the Aztecs for about a decade, and I've never read anything suggesting that the Aztecs disdained doctors, and I'd be curious to learn where you read this.

The best source for finding Aztec (well, Mexica) opinions on these things would be the Florentine Codex, specifically Book 10. It actually has several entries that discuss Physicians. The best section to start with would be the one titled, appropriately enough 'The Physician'. To quote:

'The physician is a curer of people, a restorer, a provider of health. The good physician is a diagnostician, experienced - a knower of herbs, of stones, of trees, of roots. He has the results of examinations, experience, prudence. He is moderate in his acts. He provides health, restores people, provides them splints, sets bones for them, purges them, gives emetics, gives them potions; he lances, he makes incisions in them, stitches them, revives them, envelopes them in ashes.'

This does not suggest that physicians had low standing. Instead, this would emphasise their importance to society. But wait, there's more. There is a second entry for 'The Physician'. The language is very similar, except the translation uses feminine pronouns instead of masculine ones. This indicates that women could also be doctors.

Nor are these the only mentions of doctors. The entry under 'Wise man' contains this line: 'He serves as a physician; he makes one whole.' Unless we think the Aztecs disdained wisdom, which they definitely did not, this would indicate the opposite, that medical knowledge was highly valued. There is also an entry for 'The Medicine Seller,' or pharmacist as we would say today. But again, nothing in this entry would suggest that medical professionals were poorly regarded. Book 10 also contains a list of illnesses or cures, which at least suggests that the Aztecs thought that this knowledge was important.

The only negative comments about doctors in the text are not related to doctors as a whole, but to bad doctors specifically. If we go back to the original 'The Physician' entry we can see that it continues on:

'The bad physician is a fraud, a half-hearted worker, a killer with his medicines, a giver of over-doses, an increaser of sickness; one who engagers others, who worsens sickness; who causes one to worsen.'

Note that this does not speak to the status of doctors in society, but to the Nahua concept of professional ethics. Most entries in Book 10 contain this 'Good X, Bad X,' dichotomy. The only way I can see someone concluding that the Aztecs did not respect doctors is if they read the second half of the entry as 'The physician is bad' rather than 'the bad physician,' and were unaware of this pattern of ethical dichotomies present in the rest of the text.

Source: Bernardino de Sahagún, General History of the things of New Spain Book 10: The People, tr. by Arthur O.J. Anderson, and Charles E. Dibble, (Santa Fe: University of Utah, 1979)