This is an engaging attempt to explain the violence in Syria, if a little simplistic. I would question it at two points.
Firstly, I’m not convinced that the Syrian war ever did start as a purely democratic uprising. I suspect that (as the Syrian government asserts) it was infiltrated from the start by forces whose interests had nothing to do with the advancement of democracy.
Secondly, I believe the US is more directly involved in the destruction of Syria than this presentation suggests. The well-attested existence of US military training camps in northern Jordan, for instance, suggests that the US has a very hands-on approach in supporting the rebellion and was not just drawn into the conflict unwittingly through its association with Saudi Arabia and Qatar.
Personally, I believe that the Syrian crisis is simply another manifestation of the long-term project of the US and its Gulf-State allies to maintain economic dominance of the region through weakening Iran and its allies. So called ‘terrorists’ have always been employed by Western powers when it suited them. US support for Al-Qaeda should not surprise us.
The Syrian war is complex indeed, at one level. At its basis though it is simply another chapter in the ongoing battle of Empire to maintain its money and power. And as ever, the poor and the vulnerable pay the price.