Myth? If so, what do you consider most of mainstream media to be? It is easy to highlight Fox News as right-wing, but how would you classify MSNBC, CNN, New York Times, etc.? I have a feeling most people would respond that journalists are largely on the left ideologically and sympathetically, if not wholeheartedly progressive.
There's plenty of non-left news/media orgs. WSJ, Washington Examiner, New York Post, National Review, Daily Mail, Newsweek, Washington Times. I don't think most of those would be considered fringe media.