You're reasoning doesn't add up with what's happened.
Why would the PM arrange two parliamentary votes, the first vote to get parliamentary support for a strike, the second to vote on the nature of the actual strike itself once worked out - the first vote failed, even Miliband's watered down draft didn't get any votes, the whole thing stalled.
The government's position is clear, we're not going to be involved militarily in Syria - unless something happens which totally changes the entire playing field. If I'm wrong and the PM totally ignores the will of parliament and joins in any military action with the US, you can quote me right back to this post and I'll admit I'm wrong.
So basically you're reduced to the position of saying "well governments lie quite a lot, therefore everything they say is lies"
Governmental stupidity and incompetence is a worldwide phenomena which has never been explained, but the nature of human beings and internet "truthers" is that when governments make stupid mistakes or ill thought out policies, some people (who seem insecure) seem to attribute this to some sort of conspiracy, normally involving oil, arms sales, terrorism, Haliburton or lizard men.
I'm not taking anything as "gospel" I'm undecided over what should happen in Syria, but I'm very careful in how I interpret the information and where it comes from, and won't be dragged so easily into tinhat land the way so many others seem to be.