media bias

The constant debate on whether there is more of a liberal or conservative bias in the media seems to have exhausted itself to the point where people now just choose which bias they like better when deciding what information to absorb. Some people goe as far as to observe both extremes to find a balance. What I want to know is....now that everyone pretty much agrees that there is at least a political bias within the media, how is this bias ethical? Do I just have to accept that most of the media is built upon unethical foundations or are their ethically sound reasons and consequences behind the media bias that I don't see? Would it even be possible to not have one? I personally feel that monetary, social or political agendas behind how news is portrayed are mostly unethical, but I guess if I really tried hard I could think of a few good reasons for it....