Bout time they start talking about the pre-pilgrim plague.
I don't think the pre pilgrim plague was the first or the worst either. No rational person can look at the evidence and believe that tribes of a few dozen individual hunter gatherers did some of the things they did. To build a place like Cahokia took thousands of settled people many years to build.
I think there were lots of visitors over the years who brought a lot of diseases with them. Western Europeans were just the first to successfully settle.