How can anyone seriously believe that the US is in Iraq to bring them democracy?

Bringing democracy to Iraq was not even an issue until the original justifications for war fell through (weapons of m destruction and links to Al Qaeda). The US government was allied with Saddam Hussein when he committed his most notorious atrocities. The US has also fostered a deep alliance with Saudi Arabia, practically since the county's inception. Saudi Arabia is the most totalitarian, patriarchic & repressive state in the Middle East. This country makes Iran look like a feminist's paradise and has absolutely no tolerance for freedom of expression. The US has a history of consciously fostering and supporting this brutal regime. This is because Saudi Arabia sits on a mive wealth of oil and the alliance benefits the powers of both countries. The US would rather have a dictatorship who supplies them easy access to oil then the uncertainty of something else. With this in mind how can anyone take the US claims to democracy building in Iraq seriously?