The truth about conspiracy theories is that some require considering

So Cockburn thinks one example, when ISIS came in at the end of a siege with only a few dozen government soldiers left*, weighs more heavily in the evidence than the vast amount of fighting ISIS has done against the real rebels,and that their headquarters is never bombed.
"Predictably, the western media, diplomats and the "moderate" Syrian opposition claimed that Assad not only benefited from the existence of Isis and Jabhat al-Nusra but was secretly in league with them. "Notice Isis doesn't attack government forces," people would say with shallow cynicism in Beirut, though Isis was responsible for the capture of Minnigh military air base north of Aleppo, one of the few rebel victories last year."
Robert Thouless writes in Straight and Crooked Thinking** of a trick used in argument of imputing to one's opponents a stronger proposition than they are defending. This is what Cockburn does here. ISIS has capitalised on the destruction wrought by Assad, and their continuity of interest means that only the real rebels have an interest in their defeat. It isn't Cockburn or the lizards, it is his insistence that the opposition in Syria is little more than the creation of the government in Washington that is the wacky conspiracy theory.
"But it has always been an absurd exaggeration to imagine, as your true-born conspiracy theorist would hold, that Isis and al-Nusra were the creation of the government in Damascus."
*[http://en.wikipedia.org/wiki/Siege_of_Menagh_Air_Base]
**[http://neglectedbooks.com/Straight_and_Crooked_Thinking.pdf]