To be fair, the corn used to make ethanol is no more food than a pine tree (Euell Gibbons ca. 1972 notwithstanding).
Other than maybe a couple days near the end of the growing season when field corn is palatable, you'd only eat it out of desperation.
So, while I'm no fan of corn ethanol, that argument doesn't hold water.
Corn is not food? I learned something today!