I can't read the (paywalled) article, but I did read the book "Seven Myths of the Spanish Conquest" by Matthew Restall, summarized in [1]. In said book the author posits that the Spaniards were mostly outnumbered and resorted to "theatrical violence" as a way to exert control over the population and turn them into a compliant labor force.

That still makes them pretty bad though, even if there is a somewhat rational reason to be bad. Their badness was one of their tools in the conquest.

[1]. https://en.wikipedia.org/wiki/Seven_Myths_of_the_Spanish_Con...