Greenlandic politics is held captured by a small group of corrupt populists. The population outside the city elites lives in dire poverty with massive social problems such as violence, incest, alcoholism ... And the Danish politicians are too coward to do anything about it.
Why do the Americans want to buy this place? We already let you do anything you want with it military wise. And the stuff you can dig out of the ground, you can dig it out other places much cheaper.