My take aways from the small but I watched on YouTube...
Apparently USA valiantly defended Greenland in WW2.
Which Germany never showed the slightest interest in.
Oh yes, and Greenland is strategically placed between USA, Russia and China.
Well I guess if China were to strike south, over Antarctica and then onwards across Brazil, they could get to Greenland without crossing Russia or USA.
NB. Some of the comments on the videos, in support of a clearly deranged madman, are downright scary.