Some broadcasters do their best not to ally themselves to political parties eg the BBC. It's paid for by a licence fee.
The problem at large with bias is that it operates at two levels the first is obviously when publications and broadcasters depend on advertising. These publishers/broadcasters cannot ever criticise certain products and services purely because they can't afford to bite the hand that feeds them.
The second problem is deeper and more worrying. Fox is owned by Rupert Murdoch. As an owner of so much media and satellites around the world, his empire literally has the power of political sway. In some respect he is a king maker and an un-elected one at that. It is worth remembering that the Iraq was an illegal war completely based on lies and yet Fox promoted it as "worthy" and "right" . . . one of the pay-offs for their stance was to ride into Baghdad with the first wave of American armoured forces. When bias is this strong it would be better if they changed their name to "Fox Republican News" and to be more honest about it.