I understand why. Last time around, the Iranians likely participated in the plot to bomb a transatlantic PanAm plane over Lockerbie.
We British are usually in the Iranians' crosshairs as well, although Boris Johnson's answer when told that Trump had assassinated the general was succinct.
"F-ck!"
I don't think he knew.
Our people are now trying to prepare for the reaction and to persuade the Iranians to be as calm as possible, because obviously it is pointless trying to influence Trump. No one can muscle Fox News aside.