Interesting. Iran send their goons to support a nominally secular Syrian government that is locked in combat with an Islamist uprising? You can’t make this stuff up!
The Syrian Islamist uprising is Sunni.
Iran is supporting a nominally Shiite (Alawites are Shiite to to a degree, depending on how you squint at them) ruling class in Syria.
There is nothing a bit odd here. Its the Iran-Iraq war all over again, except now its a proxy conflict of Iran vs an alliance of the Saudis and the Gulf states.
Not the first time this kind of stuff has happened. Countries ally with others with which they have very little in common all the time. The Crimean War was waged by the British and the French to limit Russian encroachments upon the Ottoman Empire. Prior to Pearl Harbor, we sent USAAF "volunteers" to staff the Flying Tigers who defended Chinese airspace against the Japanese, both of which obviously had much more in common culturally and racially than with us. And during WWII, we allied with one socialist regime (the Soviet Union) to fight another socialist regime (Nazi Germany).
The Iranians are merely allying with non-Sunni Arabs to fight the common Sunni Arab enemy. As a country that is surrounded by overwhelmingly Sunni majority regimes where persecuting Shiites is viewed almost as a religious obligation, Iran's strategic situation would be bleak even without an American presence backing those regimes up. The smart thing for Iran to do would be to ally with the US, thereby guaranteeing its sovereignty against its Sunni adversaries. But the regime is headed by delusional fools who think (or at least say in public) that they can conquer the neighboring Sunnis countries on the way towards unifying the entire world under Shiite Islam in preparation for return of the Twelfth Imam. My guess is that they view nuclear weapons as an essential tool (or shield) to aid them in the process of global conquest, which is why they are unlikely to give up on their nuclear ambitions.