Since when has it become dogma for documentarians to stay absent from their work?
I'm not saying it is, however I have a problem with the way Moore does it. He's not just in the doc, he is the doc. The focus needs to be on the issue, not on him, but it is because he's obsessed with his own celebrity.
Look at it this way, Vince McMahon runs a wrestling company but I would never in a million years say that he cares about pro wrestling. He only cares about making money and getting his face in the media in any possible fashion. Add a political theme and that's Moore to a T. Then you add in the fact that he often does more damage to the cause than good by inserting sensationalistic lies and you have someone who doesn't care about the issue but about getting screen time.