The gluten or DDG's are a by product of the ethanol distillation process, not the canola oil extraction process.
You mention another important point. The byproducts of ethanol production contain virtually the same protein levels as the original raw material. The substance Lucky refers to as DDG is Distiller's Dark Grain, a nutritious feedstuff for livestock.
So when it's all "boiled down" (heh heh), the corn is STILL fit to be used as animal food, even after the sugars are extracted. So ethanol corn serves a double purpose, reducing its overall energy cost even more.