It has EVERYTHING to do with our military being in Iraq, EVERYTHING to do with the deaths of +1,050 US military and EVERYTHING to do with the injuries of +15,000 US military.
GWB floated 15-20 excuses to pre-emptively invade Iraq, and when he landed on WMD and realized how much that scared most people that's the one he ran with.
Sounds like you bought into the WMD-Iraq connection - GWB's your man.