Not true. After ethanol is made, if the stillage is removed, the leftover DDG's are excellent animal feed, better than the corn itself in many ways.
The problem is the ethanol. It attracts water, is too solvent, and it's BTU's are too low because it is a short chain alcohol.
If we're going to use corn to ferment into fuel, it should be butanol, or esters, or something with a longer carbon chain that doesn't mix with water.