This Seems Like a Stupid Promise for Michael Moore to Make

According to this review of Capitalism: A Love Story in Mother Jones, if this latest movie in his oeuvre doesn't lead to concrete action, he's quitting movies:

After a screening in Washington on Tuesday night, Moore told the audience that if people don't rise up and take action after watching this film, that's it—he's done making movies. I can do other things, he remarked. He said this without a smile—which made it seem he wasn't kidding. But what action? Make citizen's arrests of the heads of Citigroup and AIG, as Moore attempts to do in the film? Boycott airlines that pay their pilots diddly? Become squatters in foreclosed McMansions? In response to a question from the audience, Moore did explain that campaign finance reform must be the number one priority. "You have to get the money out of politics," he said. "There is no way for us to compete with Wall Street." He also chastised the White House for endorsing a public option health plan instead of a single-payer insurance program, exclaiming, "you don't start with your compromise." Yet he urged progressives to push Obama, not pile on.
 The threat to withhold your art seems counterintuitive to me.  Either it's a powerful tool in the struggle, or in getting people to move, in which case you should keep making it to advance your cause, keep influencing movie, etc.  Or it's not influential, in which case withdrawing it is a meaningless gesture that's basically an expression of self-centered petulence to threaten to remove yourself from the creative process.