Probably many greedy reasons, but my personal favourite speculation: annexing Greenland surrounds Canada and stops any potential aid by its NATO allies in case of an invasion, since annexing Canada is one of the stated objectives of the US now.

In terms of strategy for actual national security, they already got all the access they wanted, if they wanted more all they had to do was ask. If they’re the ones doing the attacking of a common ally, though, they wouldn’t get that access. So it’s only of added strategic value to annex instead of maintaining the alliance if the goal is to attack members of the alliance.

Korean democracy is not dead yet!