I grow weary of re-explaining, but it keeps coming up.
The bias that conservatives accuse the media of is not an absolute partisanship, but a reliably leftward lean; a tendency. We don't believe that the papers and the networks never criticise liberals, only that they are much less likely to. We don't contend that the media favors people the farther left they are, but that the centerpoint they regard as neutral is actually left of center. These three sentences refute two-thirds of Eric Alterman's book.
So individual instances of making Al Gore look bad -- even unfairly bad -- or of criticising a Clinton, or reporting good news out of Iraq, do not illustrate, much less prove, a lack of media bias.