Essentially the Iran war is to control (i.e. reduce) oil going to China. As long as the straight of hormuz being closed restricts oil being sold/sent to China, tRump doesn't give a damn about other shortages as a result of the closure such as fertilizer which will see food skyrocket in price and many people starve.
The Iran War was predicated on a manufactured threat of them getting nuclear weapons. That's been the line for some time.
All reports about the initiation of the war was that Bibi wanted it and manipulated Trump to join in (against the advice of all of those around him warning that the very problem we have now would in fact occur).