Bartolomé de las Casas (1484-1566) was oficially known as "Protector of the Indians" as he became the main defender of the rights of the indigenous people under the Spanish ruling, after watching all types of abuses performed on them by the Spanish. He rejected his 'Encomienda' (Spanish way of undercovering slavery) and claimed that the only justification for the Spanish to be in America was to spread Catholicism among the natives.
On the other hand, although Columbus' relationship with the indegenous people suffered several changes along time, he always considered them as inferior human beings, who could be used to serve the purpouses of the Spanish Empire. If he changed his manners to them sometimes was only because it was convenient to him, but he never abandoned his initial opinion.