The automatic assumption that because corporations are corporations, they must be republican in support.
Disney owns ABC news, its CEO is Michael Eisner, who has a huge history of fiscal support for the democratic party and well known personal liberal beliefs, its chairman is former democratic senate majority leader George Mithell, this alone should show this idea is absurd.
If you want to know how far out of sync the left is, realize that they regularly accuse fellow liberals of conservative bias (see CBS, and its chairman, and board, most of whom not only donate to the democratic party, but who also help raise funds for it, and the chairman, in his own autobiography, refers to himself as a liberal democrat).
The 2nd reason, most liberals accuse the media of being conservative, and use the terms "media whores" is because the media refuses to publish or acknowledge conspiracy theories such as rigged voting machines (though several networks actually did, and with one exception, debunked them) or the whole "Bush planned or knew about 9/11" ideas.
The refusal to acknowledge conspiracy theories that are so absurd and without any kind of evidence whatsoever that credibility of the networks (which are already in trouble) would drop to olberman levels, alone explains that.
Conservative bias is not usually through omission, but more through what is stated, and the fact that the political beliefs of the reporter can be inferred from statements, something the far left itself, can not be able to tell, but which the right has far greater accuracy in being able to verify.
See my post number 20.