According to Argonne National Labs ( in a 2005 powerpoint ) it took:

0.74 million btu to put 1 million btu of ethanol at the retail pump.
( dirt farm to pump - the distillery takes about .39 )

while it takes,

1.24 million btu to put 1 million btu of gasoline at the retail pump.

also, it takes,

2.34 million btu to deliver 1 million btu (equiv) of electricity to your house.

Assuming ethanol plants built post-2005 ( which is half of them ) are more energy efficient that those early ones ( and I know they are ) it's taking considerably less than 0.74 btu of fossil fuel per btu of ethanol today.

People are making ethanol because it is cheap to make, and they can profit from it.
"Good for the Planet" is not their primary motive!