They're right and you're wrong. There are many varieties of corn, optimized for different uses. Corn for "corn on the cob" (aka "sweet corn") is not the same as the corn used for cattle feed, which not the same as corn used in (for instance) tortillas, or canning, or........on and on. And that is before the geneticists and "gene-splicing" got into the act.
Look up "maize" on Wikipedia
You see there? Another man smarter than I who says we cannot eat corn used for Ethanol production. No matter how hungry we are.