You mean money hungry boat techs. There's nothing wrong with ethanol and boat engines. Engines love ethanol. Ethanol was the first fuel that powered engines. America is the only country that doesn't use it in a mass production scale in higher percentages because of oil hungry presidents. 2 strokes especially love ethanol, but you have to use ethanol friendly oils.
The stuff runs cooler (cooler engine temps) and more power due to the increased compression and ignition allowed due to it's slower burn and higher octane. It doesn't hurt anything, that's all propaganda.
The local performance car scene here in Orlando LOOOOVVVEESSS E85. It's dirt cheap race gas.
http://www.youtube.com/watch?v=WIkB6Zl1wc8Why does E10 run bad in boats? Because they're not tuned for it. You HAVE to re-adjust the carb to run E10 correctly. Main thing is to make sure the float is adjusted correctly, and you need to rich the idle a tad. Usually you need to install a bigger main jet and advance the ignition a few degrees. Basically everything a fuel injected engine does automatically.
If someone opened a boat shop/service that specifically tuned boat engines for E10 gas you'd be eating well for a few years. All you need is a basic knowledge in how to tune a carb, a jet kit, and a timing light. Charge $150 for the service, profit $148.