Did you miss the Embassy takeover a few years back....and the year long hostage holding that followed? Of course....you ignore the support of Terrorist organizations around the Region and World....but then I know those are mere trivialities to you.
The situation is far more complicated than you seem to consider.
Well given US / UK / France / Israel etc etc use CIA / MI6 and their various intellignce agencies to arm and fund whoever they wish around the world and have done for last 60 plus years then using the "its only Iran" who funds terrorism falls flat on its Ass.