Media imbalance
<If true, what is your opinion on how this imbalance is maintained?
That's a good question. Theories I have heard vary. Some think that idealistic types gravitate to journalism to "save the world," in the mold of Woodward and Bernstein. Others think that the journalism schools, with their largely leftist agenda, just naturally turn out other leftists. Some think that the media just plain don't hire conservatives, so the imbalance is maintained.
Anyway, the source of the imbalance is not as important as the fact that it exists.