Can’t blame Columbus for all this. Yes, the Spaniards treated the Indians badly, but the Spanish crown—spurred by friars such as De Las Casas —enacted a legal code that gave the indians far more protection than other Europeans did, or the indians themselves did to tributary tribes. And this bit about disease. One can hardly blame the Spaniards if the indians immune systems gave them almost no protection to the aborgines. Do you think that the Spaniards rejoined to see their work force decimated?
While they probably lamented the loss of slaves, I doubt they were very broken up about the uncontested land and resources that became easily available.