Norm Geras, attempting to defend the Decent Left against Tony Judt's recent LRB piece attacking them, picks out this as the core of Judt's attack:
the habit of casting every political choice in binary moral terms
Geras then goes on to accuse Judt of being intolerant because he's unwilling to see that reasonable people might disagree over the invasion of Iraq and various other military interventions. This obviously implies precisely the kind of fault Judt accuses the Decent Left of: the reason he is intolerant is that he is casting all of these political choices in binary moral terms, because he, and those like him, refuse to believe that a reasonable person could only take one side in these disputes.
This response, obviously, doesn't really address Judt's argument, and doesn't even really adequately lay a charge of hypocrisy. Notice that Judt isn't saying there's anything wrong with casting individual political choices in binary moral terms: the critique is that every political choice is cast in binary moral terms. This is sensible, because there are political choices which ought, in all realistic situations, to be understood in certain binary moral terms: to torture or not to torture, for example. What the idea of every political choice being cast in binary moral terms suggests is an inattentiveness to the moral complexity of the world. After all, it would display a lack of moral sense to insist that most decisions about marginal tax rates and their effects on incentives ought to be understood through the lens of a discourse on Nazism. To do so wouldn't have paid sufficient attention to the various sources of moral costs and benefits, most of which have more or less nothing to do with Nazism, which properly impact on such a decision: it would be morally blind.
It strikes me that that is a perfectly respectable critique of the Decent Left: in its rush to see everything through the prism of democracy promotion and suchlike, it ignores a whole host of other costs and benefits which ought to be considered in cases of intervention, as well as the manifest shortcomings of those whom it expects to act as its agents, so, when it formulates the terms on which the decision is to be taken, they don't take into account all these other costs and benefits, or the problems of implementation. It's not so much that the Decent Left sees things in binary moral terms then, but that they see them in the wrong moral terms full-stop: anyone who trusts George Bush and his coterie of plutocrats to successfully run a democratising occupation and so was liable to cast the invasion of Iraq in the binary moral terms of for or against democracy clearly hadn't been paying enough attention to a number of things, not least how George Bush got where he is in the first place.