It’s one thing to simply cut ties because of actions they are taking or might take. But when he makes a threat “if you do (or don’t do) X, I will do (or won’t do) Y”, that’s extortion. He’s made it vague enough that Mafia lawyers are taking notes, but it’s a direct threat.
So is "If you move that plant to Mexico I'll hit you with a 25% tariff". It's not illegal.