I don't think that's true - I think it takes more energy to make a gallon of ethanol than the ethanol has in it. It's even a boondoggle energetically.
I dropped organic chemistry in 1976 or so, but from what I’ve seen people are discounting the feed value of wet or dried distillers grains after ethanol is distilled. If you are close enough to the distillery, wet corn gluten makes sense for feed, otherwise with added drying the DDG’s make outstanding feed for hogs and cattle with other additions.
Think proximity and closing the loop.