Fear of liberal bias

Talking Points Memo: by Joshua Micah Marshall: "So much of the imbalance and shallowness of press coverage today stems from a simple fact: reporters know they'll catch hell from the right if they say or write anything that can even remotely be construed as representing 'liberal bias'. "

Is fear of the appearance of liberal bias driving press coverage?

Or, is it simply that most pundits and editors and publishers are Right-Wing Repubicans?

I tend to think the latter.