The trouble is that it's unpredictable how big the crop will be before planting. As mentioned before, yields can vary quite significantly from year to year. As such, you will have periods of excess where we don't have enough storage for it all. Ethanol was promoted as a way to clean up those excesses before they turn to waste, recapturing some of fuel that was put into its growth initially.
[1] - https://www.ers.usda.gov/topics/crops/corn-and-other-feed-gr...
(The expression is not to be read literally. 'Citation needed', widespread after Wikipedia, rhetorically points to that idea in a generalized intention including "foundation needed". I.e.: "You need grounds to write that".)
Furthermore, good faith participation seeks to provide equal value to the participants. "Citation needed" offers nothing to other parties.
Apparently, according to another comment, "Citation needed" is some kind of Wikipedia slang, but a website that attempts to document knowledge is very different to a casual conversation and to try and conflate them, again, can only be done so in bad faith.
To me at least, not being an agricultural economist, the statement that the corn would be grown anyway wasn’t obvious on the surface; I too would have liked to have seen some further justification for the claim.
"Citation needed" is a purposeful attempt to dead end a conversation. It fundamentally cannot be replied to in a reasonable way. What would even be cited? There was no quote in which to cite. Maybe if I scour Google hard enough I'll find someone else saying the same thing and then I can pretend that I quoted it instead of using my own words, but what would that gain?
The ethanol situation is an interesting topic that is worthy of continued discussion, I agree. It's unfortunate that the bad actor steered discussion away from it. Oh well.