Partisanship creates the illusion of 'independence' in the media. When some new 'issues' is created, the media will respond to it along partisan lines, giving different views within a narrow range. Others will comment on the commentary, making accusations of their colleagues.
The 'illusion' is that the responses to the issue come from different points of view that somehow exist outside of the larger organizational structure and not from a media machine that always delivers the same range of responses. Really, everyone knows exactly what their role is.
Even the partisan 'extremes' are just people vying to supply meta-commentary on one side or another of the partisan divide itself. Every political discourse, even self-proclaimed 'dissident' views, buds off the official partisan discourse.
Compare this with the situation in 'authoritarian' states with a state media: their equivalent of a 'partisan divide' is not under their control. Their state propaganda vies with foreign (American) propaganda. The threat to them is real; their 'dissidents' are traitors.
