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.
America sucks more than it used to but it doesn't suck like that.