I understand that context of your post. Also, I can appreciate that is was crafted as a specific reply to another poster. I would like to expand on your thoughts and take it in a slightly different direction.
"We can't control their crazy" seems to be the justification for how we approach Iran. And many people, even those who oppose the current "war", agree with the concept that crazy must be neutralized before the crazies do something horrific. On our own soil, we see the rationale applied to the Branch Davidian Cult in Waco, TX during Clinton's presidency. Many people feel that was justified because of the reports of weaponry on their compound. In fact, I would go so far as to say many said that was the smart thing to do because we couldn't risk crazy people doing crazy things with extremely lethal weaponry.
Pivot back toward Iran. If the rationale outlined above is smart, justified, necessary, then certainly it is true for crazy attempting to enrich nuclear material to be nuclear weapon capable. That level of weaponry is on a magnitude exponentially more threatening that anything found at a compound in Texas. Furthermore, that crazy and the threat they pose is in a dangerously close proximity to the liquid which runs the planet. It is easy to see how those who favor military action come to their conclusions.
I am not saying I agree with preemptive action on crazy. In fact, I don't until the suspected threat is actually realized.