Greg Sargent makes a smart observation about Andrew Breitbart and his place in the media universe:

The conventions of media neutrality apparently require us to keep saying that "both sides do it." But let's drill down on what "it" really is. If by "it" we mean making editorial decisions -- what story to cover, what quotes to seek, who to interview, etc -- that are to some degree rooted in one's political preferences and beliefs, then yes, both sides do it.
But if by "it" we mean purveying information to readers or viewers that's designed only to achieve a political objective, with no effort whatsoever to ascertain its accuracy, true significance, or context, then the answer is: No, both sides don't do it.
Do some left wing commentators say crazy things? Sure. But high-profile commentators on the left, for instance at networks like MSNBC, inarguably hold themselves to a higher factual standard than Glenn Beck and Bill O'Reilly. (Yes, they apologized to Sherrod. So what?)
What's more, sites like HuffPo and TPM, while perhaps ideologically and politically motivated in some ways, have teams of reporters who are devoted to determining what's fair and accurate before sharing it with readers. These reporters would never run with a video like the one leaked to Breitbart without making a serious effort to contextualize it and determine its significance and accuracy. I challenge anyone to demonstrate that the Breitbart-Fox axis has any real equivalent on the left.

You can make a parallel argument, or at least a similar one, about intellectuals who work on domestic policy. You have dishonest, hackish intellectuals on both left and right. But, overall, the scholars on the left are both more independent and more rigorous, which makes for more truthful arguments but not necessarily more effective ones.