My take on this? The difference between Julian Assange and WikiLeaks and Main Stream Media, such as the New York Times and the Washington Post, is that MSM enjoys a clubby relationship with the American establishment, and by and large only expose stuff that some rogue official, such as President Nixon, has done, or who want to put the breaks on a policy, which the establishment thinks is leading the country off the edge and into the deep water, such as Vietnam. The leaks / scoops exposed by MSM on Iraq and Afghanistan served the same purpose. The establishment has decided those wars are a waste of the country's resources. What's left to do now is to get out with a little face.
Julian Assange, not only is non-American, but he has the Marxist notion -- that's Groucho Marx's notion -- that he doesn't want to be a member of the club. He is an outsider, exposing the nation's naked secrets, and is deaf to the establishment, which does from time to time exposes / leaks things, which the establishment wants leaked / exposed. The fall-out from WiliLeaks exposure of the diplomatic cables was like a neutron bomb had gone off. The establishment sees Mr. Assange as a bomb thrower and not as its tool, as are the 'distinguished' and highly paid journalists of main stream media.
At the end of the day, the role of main stream media is not to let America know about everything that is going on, only about selected things. Main Stream Media, which by the way, includes that propaganda arm of the right-wing Republican Party, Fox News, defends the club.