Michael Keefer nails the reason for Cockburn's aversion to conspiracy. He's part of the:
...<i>class of academics and public intellectuals, for whom a migration of power into military, deep-political, and corporate-media hands may . . .be difficult to acknowledge. István Meszáros has proposed that we are currently facing not merely a “conjunctural crisis” of the kind that occurred at intervals over the past century, but rather an all-embracing “structural crisis”—one which “affects the totality of a social complex” because it throws into question “capital’s mode of social metabolic reproduction” up to the ultimate limits of “the established global structure.” It would be no novelty to argue that the Bush regime’s military aggressions, together with its evident contempt for the constraints of republican governance (the Bill of Rights and habeas corpus among them) and its ever-increasing reliance on deep-political manipulations, are part of the corporatist ruling elite’s response to this structural crisis. Understandably enough, public intellectuals who are habituated to conjunctural crises in which their oppositional function was understood by all concerned, and who have in addition made a lifelong habit of ignoring or belittling political analyses which incorporate deep-political factors, have resisted the gathering evidence that these very factors have been decisive in the political transformations pushed through since 9/11.</i>
http://auto_sol.tao.ca/node/view/2417I imagine the difficulty of accepting this shift, which I would argue was going on well before 9/11, is particularly tough for smart and experienced intellectuals like Cockburn who are ideologically committed to forms of analysis that simply cannot adequately account for the events they see unfolding before their own eyes. When too much ego is involved, you get the aggressive hostility.
on edit: this piece dates to November, before Cockburn's latest article was published. And some minor word changes.