You all don't get it. The only reason Greenland isn't messed with is because it's close to us and we protect it. Trump doesn't want it, he wants more out of Denmark. His comments are the first salvo in deals to be. Denmark in fact does need to step up.
Same thing with Panama. He doesn't want the canal, he wants the US to have fair use of it. Given China's involvement in administration of the Panama Canal, a national security threat has arisen. By saying we'll take it back if Panama doesn't get it's act together, he gives us something to back off of if Panama starts making decisions consistent with our investment in building it, as well as our national interests & need to traverse the canal.