Ethanol mandates and subsidies exist because, for thirty years, Iowa has been the first state in the quadrennial US presidential primary season. They have leveraged that position into wealth for Iowans and expenses for others using ethanol as the transfer agent. President Biden is to be commended for his attempt to move Iowa out of its first mover primary spot.
Look here if you want a refresher on why ethanol mandates and subsidies are a terrible thing for the working class and the poor. This rant was brought on by a discussion of why gas prices are over $5.00 a gallon in Arizona and over $7.00 in California. Ethanol is part of the problem.