Stealing Ahmadinejad's Bicycle

This past summer, I was walking with my bicycle down a major thoroughfare in Madison whereupon a young man approached me.  

"How much are you selling that bike for?" the man asked me.  

"I'm not selling it," I replied.  "I'm just walking with it."

"But how much would you sell it for if I was willing to buy it," the man responded.

"I'm not sure," I said, hastily trying to end the conversation.  "I haven't thought about it because I'm not selling it."

The man paused.  "Then I'm going to steal that bike!" he yelled, walking away.

I've thought about that encounter frequently over the past months, puzzling over its meaning.  Now, it appears Matt Yglesias has brought his intellectual skills to the task in attempt to uncover the foreign policy implications of an exchange like this :

The idea that the threat of a bombing raid that would partially damage the Iranian nuclear program would inspire the Iranian government to voluntarily give up the nuclear program makes no sense whatsoever. Suppose I wanted Herf to give me $10. I figured maybe I could offer him various incentives in exchange for the $10. But it turns out that Herf is irrational or whatever and hell-bent on holding on to his $10. Reaching into his pocket and stealing $7 might have some merit as a response.  But threatening to steal $7 in hopes of persuading him to give me $10 would be ridiculous.

According to Yglesias, the man's threat of stealing my bike was not an effective way to get me to voluntarily sell the him the bike.  But is this really true?  Isn't the real reason I didn't sell him the bike because I didn't find his threat to be credible?  If I was certain that his threat to steal my bike was backed up with a good chance that he would actually steal my bike, I would probably have been more inclined to sell it to him.  Am I missing something here?