I think its "appropriate" to say whatever the hell you want on your own blog. And I think that Michael Arrington has put out more than a few articles that were "not that great."
I'm laughing at the fact that I understand your analogy, but I don't think its true. In my opinion, the punditocracy could use a little bile aimed its way, because it's fat, insiderish, and generally has become what it sought to overthrow. Jon Katz had no bile - he was more of a Steve Gillmor, did too much drugs, irrelevant hippie type.