If you're suggesting a causal link between a partisan media and social violence, I really question it. I believe both intense partisanship and social conflict are dependent variables.
I think the example of Radio Milles Collines in Rwanda and Radio Television in Serbia during the Bosnian Civil War are strong arguments against your thesis. Both were used to spread false atrocity stories and mobilize communities to "self-defense." As one Serbian dissident editor put it, "You must imagine a United States with every little TV station everywhere taking the exact same editorial line --- a line dictated by David Duke. You too would have war in five years."