The sinister idea of converting food into combustibles was definitively established as the economic line of foreign policy of the United States
Not foreign policy, it is a subsidy to the corn growers here. Corn -> Ethanol is not a particularly cost or energy efficient process, there are other crops that would be better. But the corn growers are a powerful lobby, so they get the subsidies and the business.
The damage it does to others is only incidental. Heck, in the long run, getting subsidized US corn out of the market will probably help many countries, as it will make local farmers more profitable.
Jay