An organization known as the Renewable Fuels Association has this to say in a news release

As has been understood by Congress time and again, removing the secondary tariff on imported ethanol is bad policy. The tariff exists as a protection for American taxpayers from having to subsidize foreign sugar and ethanol production. Removing it, therefore, would force taxpayers to support sugar plantations in Brazil, for example.

If you can't tell already, the organization isn't quite what it pretends to be. I mean seriously guys ... do you think anyone is stupid enough to buy the argument that US taxpayers should pay to subsidize corn ethanol production, and therefore pay higher prices, just because you don't want to have to compete with Brazilian sugar based ethanol? So, buying products from overseas producers at market rates is now classified as "forcing taxpayers to support" them.

Oh right ... as you point out, congress, time and again, really is that stupid. And there's this:

"During his tenure in the U.S. Senate and as a presidential candidate, President Obama has been a strong supporter of America's evolving ethanol industry," said Renewable Fuels Association president Bob Dinneen. "Our industry has long appreciated the support of the President and look forward to working with him." Obama said, "we think the tariff has a role in maintaining a vibrant renewable fuel policy."
OK, let me rephrase: is anyone other than a politician, and the 30% who still strongly support Obama, stupid enough to buy that argument?