I think it is simply an area of utmost strategic importance for the USA.. Greenland is a linchpin for U.S. Arctic strategy, offering military advantages, resource potential, and a platform to counterbalance rivals like China and Russia. (And the USA has a NATO military base there anyway, while the NATO-member Denmark has Greenland as a colony; better for Greenland to be a territory of the USA!)
”Nothing more” than that I believe!