By the way, how many Incas died in ritual sacrifice on Pagan altars? I think I read somewhere that Christians put an end to that practice.
Both. Far more from disease, no doubt. But milions of natives died in the mines, and on the plantations of the grandees. The actual numbers will never be known, as there was no reliable census pre-Colombus. Read up on the history of the Spanish empire in this hemisphere. It's not pretty. The reason they went to the trouble of importing Africans is because the indians were dying off. Genocide isn't new in the world. The commies don't have any monopoly -- but they sure did set some new records.
What the Christian bashers forget to tell is that Cortez with just some 300 men could have never conquered Mexico without the help of Indians who were sick and tired of the murders and oppressions of the Aztecs. Pizarro, with a rag tag army of some 200 men could have never conquered the Inca empire either if it had not been that the people were sick and tired and drugged out from the mistreatment of their rulers.