Look at the stuff he's been putting out in his career. He started out slow with Roger and Me, but he has been getting bolder and bolder with each new production. BFC finally tipped his essential disdain for how America is (the point of it wasn't so much a critique of guns or gun laws but American society).
I know how extreme Michael Moore really is, he's getting bolder and bolder in revealing it as his stature and fame grow. I'm basically saying, being such an egotists and such a freaking moron, Moore is going to hang himself with his own rope. Except for all the smart and sophisticated urban/overeducated types who agree with him, he's going to completely lose the public's ear.
Basically, I think Michael Moore is holding back how he actually thinks. When he thinks he is safe or above criticism, he'll let loose and we'll see his ugliness in all it's glory. I think it might come with his "Fahrenheit 9/11" movie.