I think that we can continue to try to make our discussion better. For better discussion of culture on the Left, I think that several things have to be accepted by artists and critics alike. (The following I offer also in the spirit of self-criticism as well.)
Left critics of culture must accept that art doesn't have direct & immedite effects on the state of class consciousness, social relations, struggles, and so on. The relationship between art and its audience is complex, and I think that truth of art had better be thought of as residing or (better yet) emerging from structured and yet relatively open-ended transactions between art, the audience, and social relations & ideology in which they are embedded. In other words, truth of Michael Moore's film, or anybody else's work for that matter, is not sealed inside the finished product. Left critics' job includes explaining how we can _make use of_ art so as to make truth emerge, not only out of cultural products created by left artists but also from the works created by those who do not share our politics.
I think that Carrol Cox said that the audience for left-wing culture must be 'created' or something to that effect, and I think that he's right. Discussion of the kind we are having here, I think, is important for the creation of such audience, as important as actual attempts to use whatever cultural product available in the context of practical politics.
Left critics of art should be also aware that there is usually an overwhelming burden of representation on left artists as well as artists from oppressed groups (such as blacks, women, sexual dissidents, etc.). Since the corporate media do not and cannot offer many chances for representation by such artists, and correlatively, those of us on the left and/or of the oppressed groups have so few chances to see any work that really speaks to us, we tend to expect the impossible: for a single work of art to get everything right. What is to be remembered here is that cultural production has to be a collective endeavor, as is the case with everything else important to the Left. We do not need perfect art. We need many examples of usable art (among which I count Moore's work), because art is only meaningful (to the Left, that is) when it is actually used.
That said, artists on the left must accept that criticisms from left critics come not out of malice but out of our desire for better and more useful representations. Artists may disagree, of course, with any and every criticism of their work that may reach their ears. However, artists should at least be aware that their primary job is not to create art that receives nothing but applause, but to provide an opportunity for discussion, criticisms included. And receiving feedback from an active and engaged audience is a necessary and even useful moment for artists.
Yoshie