Where do these people get the Idea the Iraq war was for oil?

If the US military really was in Iraq for oil, then how come we don't get any of it? If we really wanted to conquer Iraq how long would it have taken? if we didn't care about killing civilians, we would have owned Iraq in a week. The first gulf war was for oil, no one can deny that, we went to war to protect our oil supplies in Saudi Arabia, Usama (that is how u spell it so dont correct me) Bin Laden offered Saudi Arabia his help but they chose our military instead, thats why he got pissed and attacked us, and what was the real reason to go into Iraq? yes to overthrow an evil dictator but if we went in for that sole reasons we would be in about half the countrys in the world right now