You right, and I believe it has to do with the fact that the sitting president of syria belongs to a shiite group of islam which means that they are despised by the Saudies and the rest of the oil rich gulf nations. It's a war between Shia and Sunni currently going on. Iran backs Syria because the rulers are Alawies which is a sect within Shia. It's politics in the end, because if USA and its allies suddenly backs Syria then the OPEC (Sunni) community will start fuck things up economically.