Oh, there are definitely lots of New England liberal environmentalists, including some who live on the Cape and the Islands, who are solidly behind this idea. I’ve worked with some of them on a local “green power” campaign when I was living in Rhode Island. IMO, most of the opposition to the windfarm is being generated by a comparatively small number of people with disproportionate access to the wealth, publicity, and political clout required to sway public opinion.
I think a lot of the local resistance is, as I mentioned before, sheer distrust of the unknown, and a lot of the rest has been carefully fostered by anti-Cape Wind PR campaigns. And a recent study seems to bear me out:
Where did so many residents, and even members of Congress, get the idea that the wind turbines will be bad for fishing, bad for wildlife, and an ugly blot on the landscape, even though environmental impact assessments have all indicated that these won’t be serious problems? IMO, from the PR materials put out by the various anti-Cape-Wind front groups for a few powerful individuals. (To be fair, those groups do also include individuals and organizations genuinely concerned about the potential drawbacks, but AFAICT most of their clout comes from local NIMBY bigwigs.)