The genocide didn't happen solely after the first contact, the massacre of natives lasted centuries. Many nations were wiped out in the XIX century.
And a quote for you
Proponents of the default position emphasize attrition by disease despite other causes equally deadly, if not more so. In doing so they refuse to accept that the colonization of America was genocidal by plan, not simply the tragic fate of populations lacking immunity to disease.
Professor Roxanne Dunbar-Ortiz
Interesting, it played fine with Libretube (piped frontend app) installed.