Let me make one thing clear. By all the evidence, Columbus -- as an explorer -- was a pretty good guy. While noting that he could enslave and conquer the Indians trivially, he elected not to.
Instead of forcing the natives to help him in the darkest hours of his last expedition, he predicted a lunar eclipse and got their willing assistance.
He was attacked by a native tribe (the Ciguayos) and defended himself and his crew. He took some hostages back to Spain, but one could hardly see that as unjust.
He intervened honorably by rescuing two native boys who had been castrated by their captors.
The worst thing he did was bring disease to the New World. No one in the world back then knew that this was a danger. It wasn't until 100 years afterwards that Leeuwenhoek invented the microscope and discovered germs.
Even that's not that bad. His expeditions likely brought syphilis to Europe and resulted in an estimated five million deaths, so it was at least fair.
Don't blame him for the actions of Sepulveda, Cortez, Pizzaro, or the others who came after him.
