Years ago, I read an interview with Leonard Cohen who, as you might remember, became a Buddhist monk. He stated that in the monastery, you’re free to do pretty much anything - in your free time. Listen to rock music, take drugs, no-one cares.
It’s just that you don’t have any free time because every day is 100% structured.
Greenland is just the low-hanging fruit, an easy target. Something for the masses at home. Taking it won’t take an afternoon. In fact, they’ll just show up, plant a flag, next to it a “No Danes” sign, then call it a day. Then make a biiig celebration of it at home so everybody is distracted while they irreparably dismantle American democracy.