I think Kurt Andersen is onto something: 

...I don’t know many of those fierce Clinton supporters, because most of my friends and acquaintances are writers and editors and cultural impresarios of one kind or another—members of “the media”—and there are precious few Clintonites among them. Because almost as much as geography is dispositive in spectator sports—if you live in New England, you’re bound to love the Red Sox and hate the Yankees—demography is dispositive in this year’s Democratic race. And the great majority of media people are members of the same (white) demographic cohort that has rejected Hillary and voted for Barack—educated, more-affluent-than-average residents of cities and suburbs....

So it’s ironic that the media and their fellow upscale Americans are now disposed to like Obama precisely because he resembles them in so many ways. The difference is he’s relatively unsullied, an exquisite, idealized version of themselves: educated, thoughtful, twigged to nuance, a lovely writer, well-traveled, witty, cool, dignified, candid, a little quixotic, a clued-in grown-up but not yet ruined by the ugly facts of Washington life.

I think the Clintons may also have been irrevocably damaged by a sense that they excessively bullied and manipulated the media. For a time the press acquired a kind of Stockholm Syndrome towards the Clinton machine. But as with the fall of a dictatorship, at the first sign of weakness every pent-up frustration burst forth into outright rebellion. It's more complicated than that, of course. But that's a healthy part of it. 

P.S. A related Howie Kurtz story correctly notes that Obama's media treatment is in fact getting tougher. TNR contributor David Greenberg adds an interesting theory:

Still, says David Greenberg, a Rutgers University professor of journalism and history, the coverage could be far worse. For journalists, he says, "there has been a real infatuation with Obama that has served as almost an unconscious restraint" as many became "taken with the idea of demonstrating their tolerance and America's tolerance by electing a black candidate."

(Kurtz's story comes with a bonus John Judis cameo, too.)

--Michael Crowley