It does contrast with the alternative which was pillaging and laying waste to conquered lands and not taking adult male prisoners as was quite common during those times.

Also, when the conquistadors went about they would often find warring parties and play sides. This made it easy to divide and conquer and gain cooperation of some locals and eventually see their culture and values prevail. Kind of the same William the conqueror did (kill the nobility/chieftains and let the cooperating peasants live)