Maybe the cartoon was fostered by folks trying to grind an axe for other impractical fuels like hydrogen, but still this does not look like a claim that 1/2 gallon of oil goes solely into pesticides for a bushel of corn — but that it goes collectively into all the activity involved in producing the bushel, harvesting it, and processing that bushel into ethanol a la Arthur Daniels Midland. And the poison suit simply is a caricatured way of showing this ain’t watering the corn... gee whiz the whole operation isn’t located together either, are we going to quibble about this too.
It’s a completely false claim, so the source doesn’t matter, neither does your quibbling.