Co-uses and co-products isn’t the question here. The question is whether it makes sense to mandate ethanol as an additive. NOTHING I have seen with respect to mileage, efficiency, non-harmful effects on engines - or even COST supports adding it to the “co-product” category for the sake of saying “corn is good.”
To me co-products is the issue. It means that all the studies about cost, pollution, etc. are wrong.