Actually, they thought he was a returning God, so they were cautious. They had never seen horses, armor or white men before. In the end, it was the diseases that the white men brought that took most of the natives down. And Cortez was justified, because he was told by leadership that there cause was just. They were to rid the Aztecs of the WMD's (weapons of manual destruction), which were plentiful and were clearly a threat to the Spanish empire.
Damn Malinche! That backstabbin traiter women!! (She was Cortez's translator and lover, and sold her people up the river.)
