This is the same type of extremely limited thinking that we saw here on imgflip after Trump created the Space Force. Trump is very forward thinking, and sees the big picture in ways libs, the media, RINOs, etc., simply do not.
Let's put it this way... do you want Russia and/or China controlling Greenland? Controlling the seas around it and all its natural resources? Have you seen what those two countries do when they want more territory? They don't offer to buy or lease, they take. Just check up on what China is doing in international waters in the South China Sea, particularly against the Philippines.
For the security of the free world, it's better to let us protect Greenland and its abundant natural resources, rather than expecting an extremely incapable Denmark to do so.