I'm not part of that interest group, I'm just regurgitating facts I read.
To add to that, when they were experimentiing with ethanol, they needed a good compromise between cleaner combustion & compatibility with gasoline engines. 10% I believe was that number. If you read your car/bike manual they don't recommend using greater than 15%(don't quote me on that) ethanol.
Some people preach such hate for ethanol, but there was a reason it was mandated in most gas. Personally I prefer no ethanol, because of more energy for the same liter of fuel