What's the incentive for a ship captain to risk this? Even if they're more confident than almost everyone else that it's a bluff and think there's a 95% chance Iran does nothing, a 5% chance of you and your crew being incinerated is a crazy risk to take.
Would you go to your normal job tomorrow if someone who has a history of carrying out threats has threatened to kill you for it?
You can't imagine someone who would go to that job simply because the owner hired a bouncer and they have a different faith in authority or really mean looking bouncers than you?
I can spend 10 minutes looking at demographics and tell you the world is not explainable if the measuring stick is my own risk tolerances.
Would you go to your normal job tomorrow if someone who has a history of carrying out threats has threatened to kill you for it?