I agree with you. There are two things that need to be shown before ethanol can make its way a a viable motor fuel. You have to be able to run the whole process on ethanol. Ie the energy balance has to be such that you can bootstrap it, and secondly it does no good at all even if there is a positive energy balance if it takes too much agricultural land to give a net gain of ethanol. We don't exactly have an unlimited supply of crop land suitable for growing corn. looking at Pimental's article gives you a realistic feel for what the ethanol addicts wish to deny.
On the other hand, if you're serious about this guy Pimental, take a look at post 207.