You have a point there. Perhaps this was some sort of judgment call. But Bush and more importantly the US lost a lot of credibility by going into Iraq for "false" reasons. IMHO if there really were WMD's, it would have been better for Bush to let the world know.
The UN spent close to 10 years destroying Saddam's WMD. And at the end, they had Saddam's own documentation stating there was more, but Saddam could not find it for them. So there had to be WMD somewhere.
If you fell for the agitprop of no WMD, then you also probably leaning to the stop AGW Climate Change programming.