>> A much more likely explanation is that the leak of the existence of the tape was not planned and the tape itself is damaging to "The Cause", namely the defeat of George Bush in 2004. <<
I think the whole bruhaha with Miramax refusing to release the film is a red herring. They are in cahoots with Moore. This allows the shlockumentary to get high praise and awards without being seen (Cannes). It also gets lots of *free* publicity.
I expect some "brave" company to release the film in early October just in time for many American voters to see it right before November 2.
There is no question in my mind that you are right about this. Disney wants this picture shown but feels for some reason that they need some political cover. The sale to the Miramax executives is just too transparent for words of course but is apparently good enough the Eisner Clan.