First of all Saddam was an official US ally all throughout his worst atrocities, including the war with Iran, the brutal, oppressive dictatorship, the use of chemical weapons on the Kurds and similar massacres, in fact that is where he got both the approval (yes, unlike today this was a time shortly after the first Gulf War where nothing on this scale happened in the region outside US control), weapons and weapons programmes, up and until the attack on Kuwait. There even was a civil and military coup attempt against him but the US refused to aid the rebels, and continued to support the murderous regime as long as it served US economic and political interests.
This went on especially through the Reagan years until those same people came back into government (the Bush administration(s)), and where good ol' Saddam now suddenly was an outcast, enemy to the World society and a
terrorist. Thus it cannot be for 'democracy', 'Iraqi freedom' or whatever other contrived propaganda that has been spewed to manufacture consent. It is simply self-contradictory and facts to the contrary are well-documented in the historical record. And we all know it was against international law and that the first, incredibly weak premise for war (WMDs) were an utter farce. The US also has an unflinching record of supporting dictatorships over democracies, as they are easier to control, especially all over the Middle East and South America, but also in Africa and Asia, from the Apartheid regime in South Africa and to the various despots of Indo China.
http://www.foreignpolicy.com/articles/2013/08/25/secret_cia_files_prove_america_helped_saddam_as_he_gassed_iranhttp://www.dailymail.co.uk/news/article-2402174/CIA-helped-Saddam-Hussein-make-chemical-weapons-attack-Iran-1988-Ronald-Reagan.htmlhttp://en.wikipedia.org/wiki/United_States_support_for_Iraq_during_the_Iran%E2%80%93Iraq_warSecondly, the Iraq war was about oil (and other things of course but mostly oil), more specific the
control of oil. This is from the mouths of US policy makers themselves. We have learned from declassified government documents from among others the Truman, Carter, Reagan, Nixon, Kennedy, Clinton and Bush administrations, that the control of Middle East oil is and has been a core strategic principle for US world domination (yes, world domination is a US principle, too) since WWII destruction of Europe brought about a chance for American hegemony (for a time).
It is as you correctly point out not about using the oil for American consumption but more importantly the diplomatic leverage gained from controlling one of the world's largest concentrations of oil.
In a 1945 memorandum to President Truman written by the Chief of the Division of Near Eastern Affairs in the U.S State Department, Gordon Merriam, stated:
Albert A. Berle, one of Franklin Roosevelt’s closest advisers, particularly in relation to the construction of the post-War world, years later remarked that controlling the oil reserves of the Middle East would mean obtaining:
'substantial control of the world'.
A recommended comment on the conflict: