The argument for adding ethanol is it reduces the requirement for oil and because ethanol is derived from food or plant matter, a renewable resource.
So it's presented as a 'green' choice politically although my understanding is most true greens don't accept the argument.
As for differing views - very much so. However, my chemist friend is the real deal.
When you see a view on ethanol in fuel, not only have you got to ask, "what are the qualifications for someone to say that?", but also "who do they work for and what's their personal interest?". It's not helped by the fact that some institutions that should know better have been taken in. While I normally recommend the FBHVC (Federation of British Historic Vehicle Clubs) their advice on ethanol in petrol does contain a few errors that ought to be seen through by anyone with A level chemistry (I have, and can).
The biggest risk is corrosion due to water in steel tanks and pipes, with a possible effect of ethanol on some plastics and natural rubber. While petrol is a far better solvent than ethanol, there are some plasticisers that are soluble in ethanol and not petrol.
I've said everything I can and am unlikely to contribute again to this thread.
