I think the strategy of the Dems is to say "Fox is biased" so long and so loud that it gradually sticks in people's minds - "A lie repeated often enough becomes the truth."
Fact: Fox is owned by Murdoch/News Corp.
Fact: In home market of Australia, Murdoch's rags are the most liberal.
Fact: Murdoch is a businessman.
When entering the US market, where was the opportunity ?
More liberal pap ala CBS NBC ABC CNN ?
NOT
What pisses off the libs is Fox's success (a conservative message)