Greenland belongs to the Greenlanders. They live there. It is their country.
They are legally Danish citzens. Greenland is largely self-governing, with the possibility of becoming independent if they choose to.
Denmark can't "sell" them or their country because Denmark does not own them.
And after a number of centuries and some debate, a general consensus was arrived at that selling people is not ethically acceptable, you know?
Even if they wanted to, Denmark can't "sell" Trump Greenland any more than the UK could sell him Scotland.
Also N.B. 85-90% of the Greenlanders are Inuit.
I am very certain that this is absolutely about thinking that Native people don't
really count as citizens and they don't
really own their land; it is Terra Nullius, and they can be sold off in a deal between the "real" nations of Denmark and the US.
(Or their land can be sold out from under them and they can just be forced elsewhere, which I'm sure Trump would be just fine with.)
If the US wanted to try to ethically acquire Greenland, it could talk
to the government of Greenland and offer them a great deal with significant benefits if they wanted to become independent and then have a free association deal with the US.
Or rather, it
could have, maybe, because now the Greenlanders are fucking pissed off and scared over the threats and offers to buy them, and if they have to choose between the US and Denmark they are unambiguously choosing Denmark:
https://www.bbc.co.uk/news/articles/cvgx8w4pgk0ohttps://www.theguardian.com/world/2026/jan/14/us-invasion-threat-greenland-trump-denmark