Check out Todorov's The Conquest of America: The question of the other. On the first chapters he analize several letters from Colombus to different people, the kings, the pope, the guy that loaned money, were you can see Colombus expresing on the topic his readear would care in different ways. Theres plenty of "dikishness" to be found there. Remember also the fact that the brutality of Colombus allowed to appear some monks defending the natives (most important is Bartolomé de las Casas). It is true the good men didnt stop the slavery, but the conditions on the relationship between spanish and native wont be that harsh as the first colony of Colombus (total extermination by war or labour). At the end there was the economic issue; conquerors as new nobles wont work whit their hand and will avoid bringing african slaves if they had the american natives. Yeah, still thousends or even million of death started whit Colombus, but wasent that persistent. Remember that spanish colonization allowed mixing whit the natives, so theres space also for some happy tales here and there. (one of the Cortez scouts was founded full of tatoos living whit the natives, when other scout party found him he refused to go back*).

In places whit high number of native and complex systems of society, as the Incas, some native retained their nobelary status previous the hispanic conquest while forced to adopt their culture. Theres a situation were a noble Inca is taking a slave punishment, one of the spanish autority notices his nobility and makes a scandal about how this men is begin punished in a way intented for lower classes. (hes fault was related to a faith issue*).

If we try to get in the mindset of the time, Colombus started a process to save all natives of america by introducing christianity, saving their souls. Teach them "civilization" and such porgress deeds. As is noted, this is a eurocentric vision, and as they were discovering the "new" world, theres not much room for other kind of scoope to see the world other than the marching of time and the conquest over barbarians. The interseting is that this new world, would in theory affect the european cultural production introducing new topics, the idea of the "good native" and the "new world" could inspire stuff like Moro's Utopia and the liberal philosophy when talks about the "state of nature" pririor to society.

*Sorry but i dont remember the sources, but they are legit for sure. Cortez scouts i am sure is in one of the several Chronicals about the conquest of Mexico, could Bernal Diaz or Cortez letters (anyway pretty fun readings). The inca punshiment i saw it in a document in class about american conquest.