This seems to be some form of strawman, given I never even implied there was no attack. Merely that it was misattributed according to leaked documents written by chemical experts.
Also, Assad was by all accounts winning the war and pushing back on all fronts at the time. Do you think he's such a lunatic and so strategically bankrupt that he'd launch a chemical attack on his own people while he's winning? Or is it more likely that ISIS launched a false flag attack using chemical weapons that we know they have in order to get the West to do their bidding against Assad?
The Syrian war is a mess, and there are no good guys. The US-backed rebels commit war crimes and behead children, for example.
The source of leaked documents really doesn't concern me as long as they are authentic. For argument's sake, if Snowden was a Kremlin double agent I wouldn't care because he revealed genuine government wrongdoing.
Attacking the source generally isn't a valid argument, especially given the authenticity of the information.