As someone who wrote "Getting Whitey: Michelle Obama's Secret Negro Agenda" satirizing the right's twisted vision of the aspiring black first couple, I understand what New Yorker cartoonist Barry Blitt was trying to accomplish with his now-notorious cover art. However, he did it poorly, and in doing so, he advanced the point-of-view he tried to satirize instead of deflating it.
In his own defense, Blitt told Huffpo's Nico Pitney:
I think the idea that the Obamas are branded as unpatriotic [let alone as terrorists] in certain sectors is preposterous. It seemed to me that depicting the concept would show it as the fear-mongering ridiculousness that it is.
If only Britt had depicted the concept. Instead, he simply parrots the concept with no context. He parrots the concept; and parroting is not parody. For instance, had he depicted a right-wingish figure seeing the regular couple as the Muslim/militants he depicted, he would have achieved his aim. We would have seen the reality, and seen how certain individuals choose to twist it. Instead, he offers the right-wing narrative with no context whatsoever -- thereby reinforcing it.
The kind of double-barreled image true parody would have required is difficult to pull off. What Britt provided was comparatively easy. But it's hard to believe that the editorial staff of the New Yorker did not see this straight depiction of Obama and his wife as militant/Muslim terrorists for the Red State red meat that it is.
There seem to be two possibilities. The first: they truly find the idea depicted in the image so ridiculous that they couldn't conceive of anyone taking it seriously. However, if that were the case, there'd be no need for the satire in the first place. Attempting to satirize it acknowledges the idea's prevalence.
The other possibility is that somewhere, deep in the recesses of their upper east and west side white minds, lurks a restive "fear of black." To provide such an image without context is to accept its message to some degree. No similar cartoon would have ever appeared about a white candidate.
Where is the drawing of the left's vision of John McCain as an adulterous gold digger, with McCain hiding his current wife behind his first wife's hospital bed curtain? That analogous image would never appear on a New Yorker cover.
There was probably no conscious malice here -- just laziness and latent "fear of black."