Robert S. McCain has a good post on why there are so few conservative reporters.
I think all of his points are valid. I don't think that we should overlook the close-mindedness of the liberal MSM. (Is that redundant?)
When the rare conservative reporter breaks a story, the rest of the guild usually ignores it. I made that point here:
Bias can also be a factor in how other journalists treat the "scoop." Both Bill Gertz and Sy Hersh have many talkative contacts in the Pentagon. The rest of the MSM is ignorant about those source's identity, credibility, and competence. Nevertheless, ABC or the LA Times are far more likely to run with a Hersh story that one by Gertz.
Why? How can the reader/viewer be certain that this has nothing to do with Hersh's reflexive anti-Rumsfeld slant or Gertz's pro-brass slant?