The medieval warm period was what destroyed the Dorset culture, as they mostly practiced Ice Hole Fishing for larger sea mammals, rather than using canoes to fish. So when the weather warmed and there were more holes in the ice, it made their primary way of gathering food impossible. This same medieval warm period was also a massive boon to the Thule, who benefited from the warmer conditions and so spread out much further. Inuit legends about the people living there before them describe them as skittish and avoiding contact, there aren't stories of impressive conquests or justifications for massacres that we see in folklore that describes one culture wiping out another, additionally, since the two societies had very different lifestyles, they never really competed for resources, so it was unlikely that the Thule ever "wiped out" the Dorset.

This dude literally took out the wikipedia page on the Dorset, ignores 90% of it that actively contradicts his claim and them cherry picks a phrase and pretends it says opposite of what it actually says. This is advanced level racist bullshit.