Not sure if you are right or not but your analysis made a lot of sense and got me thinking. To add to what you said - what if Bush knew Saddam spirited the WMDs to Syria and still attacked and doesn't want everyone to know that?
Its just a thought, but one that makes sense to me, or at least helps make sense of things that otherwise make little sense.
"Spirit(ing) the WMDs to Syria" would actually bolster his case for war. It would reflect Saddam's willingness to hide that he has the WMD and also his willingness to export the WMD.