It's important to remember that Spanish treatment of American native laborers was so bad that one early 16th-century observer,   Bartolomeo De Las Casas, argued for the importation of African slaves as a REFORM! Read his treatise "A Short Account of the Destruction of the Indies" to get an idea of why Columbus seems so repulsive to us now. The destruction of America, both its peoples and biome, BEGINS w/him.

Conversely, Las Casas later recanted his support for ALL forms of slavery and can be called the first modern human rights activist. In other words, it can be said that the modern concept of human rights advocacy--advocacy grounded in a critique of inequitable power relations--begins as a reaction AGAINST Columbus and his "discovery" of America.  

https://en.wikipedia.org/wiki/A_Short_Account_of_the_Destruction_of_the_Indies