Given the other tagline is TACO[1], I guess the “who's going to stop me?” is less rhetorical and more literal.
[1]: https://en.wikipedia.org/wiki/Trump_Always_Chickens_Out
[1]: https://en.wikipedia.org/wiki/Trump_Always_Chickens_Out
Denmark and/or Greenland needs to seize those containers, keep them under armed guard, and then give Greenland Energy a reasonable deadline to come and retrieve them or else they'll be destroyed.