The New York Times claims "All the News that's Fit to Print", and no competing newspaper or broadcaster disputes the claim. Conservatives (e.g., the Media Research Center) critique journalism's tendentiousness on a daily basis but the signature of the journalist is a get-along-to-go-along posture with respect to the credibility of any other journalist.
The prospect of competitive advantage to be gained by undermining the credibility of a given member of the competition is outweighed by the prospect of defending against a reply in kind by all of the competition. It is a case of "mutually assured destruction." Any journalist (e.g. Bernard Goldberg) who breaks the tabu on discussing "Bias" is instantaneously "not objective . . . not a journalist." As Ann Coulter (Slander) clearly understands, journalists cannot start using that technique on a conservative; they would have to stop first to be able to do that.