These assholes get away with anything, because they are muslims. It's ok to lash out and attack (Israel, the US, France, Britain, Turkey, and riot in the streets of Denmark) but it's NOT ok to attack back.
Iran (under the auspicions of the "Muslim Hordes") already fucked with the US in the Barbary conflicts in the mediterrean. They never stopped that fight with us, it still goes on.
It's SAFE for the muslim to threaten the US, because our hands are so tied with proper responses. We won't even call them names for fear of retaliation and losing an election.
Iraq did these things, we went to war with them, and now everyone is bitching about how unfair we are. Iran is doing it because IT FUCKING WORKS.