re point one the __lowest__ plausible percentage of North America and South Americans that died of disease before ever hearing a rumor of it source is 90% and has a fair chance of being higher, the disease front traveled as quickly as the natives, refuges from one dying village to the next, or people coming to investigate why no body has visited from the next community over in a while. The deliberate atrocities later were just a mop up action in the larger picture.