The major oil buyers thing in Libya happened around 2005 or so when Qaddafi decided to reconcile with the west in exchange for profitable oil contracts and an implicit promise that we wouldn't bomb the crap out of him the first chance we got (joke's on him). So we were actually bombing a country where we'd already gotten the oil access, not the other way around.
As far as the oil trade in general, it's been dominated by cloak and dagger stuff for decades, in the US we have a partnership between the oil firms and the gov't where the gov't goes to bat for them in foreign countries, and in return they don't pay their taxes. In China, there's less of a formal division between the two so it's simpler. But both cases are the same.
And I'm not saying that's right, but it's a lot more complex than "the US controls Iraq's oil". We don't, really, we have to bribe people and do underhanded stuff on equal footing with everyone else at this point.
As far as the oil trade in general, it's been dominated by cloak and dagger stuff for decades, in the US we have a partnership between the oil firms and the gov't where the gov't goes to bat for them in foreign countries, and in return they don't pay their taxes. In China, there's less of a formal division between the two so it's simpler. But both cases are the same.
And I'm not saying that's right, but it's a lot more complex than "the US controls Iraq's oil". We don't, really, we have to bribe people and do underhanded stuff on equal footing with everyone else at this point.