How Spaniards Could Treat Indians Savagery in the Age of the Enlightenment?

Reading the book “The Conquest of American: The Question of the other” by Tzvetan Todorov, it becomes very clear that Spaniards treated Indians with such cruelty and savagery.   Indians were not treated as humans; they were tortured and killed “In order to be more secure, the Spaniards take him (Cazonci) prisoner; when they fail to obtain satisfaction, they do not hesitate to torture him and his family: they are hanged, their feet are scorched with burning oil, their genitals prodded with a metal rod” (page 97).   Indian women were raped, their children were abused; all were infected by foreign diseases. They also “had carried off the wives and daughters of a great number of chieftains” (Page 58). They did not hesitate to destroy the Indian history, religion, and tradition. According to the book, they “burned the Mexicans’ books in order to wipe out their religion, they destroyed their monuments in order to abolish any memory of a former greatness” (page 60).
One may wonder why Spaniards even dared to treat Indians who were already settled in their land and were land owners of the American continent so savagery or even barbaric in the age of the enlightenment? To answer this question, I would like to offer three different reasons. The first two reasons are drawn from the second chapter of the book: Conquest. While the third is drawn from my own understanding and interpretation of the readings, which might be briefly mentioned but not emphasized in this book.
1) Refraining to take action against the Spaniards: One of the main reasons that led to savage treatment of Indians by the Spaniards was the passive behavior of the Indians toward their invaders.   I personally believe that their passive behaviors were mainly due to their strong beliefs in superstition (although the author does not use this word rather he says that the way of communication for Indians was between man and nature and not between man and man). Indians believed that “the arrival of men greedy for...