Yes, I think epidemics are "natural". Unless you think XVI century Castille enginereed bio-weapons.Do you think those epidemics were "natural"?? This is due to all those deportations and it's actually much worse than mass killings since the Natives suffered much more.
And suffered much more? I don't have your luck and don't own a sufferometer but having between 75% and 90% of the population dying out doesn't seems that great.
The US government destroyed their traditional lifestyle, which automatically led to those devastating epidemics.
Let me get this straight : US native policy in the XIX century, managed to create XVI epidemics?
That raises many interesting questions, the first of which : is that a trolling attempt?