I am surprised the author did not discuss Herman and Chomsky's propaganda model: http://en.wikipedia.org/wiki/Propaganda_model

I believe it accurately predicts mass media's biases in this situation.

The propaganda model says that propaganda is an emergent phenomenon in democratic societies. Similar to how macro ant-colony behavior emerges when individual ants follow simple pheremonal rules --- propaganda emerges when journalists, managers, PR agents, government officials, etc. each optimize for their local objective functions.

The relationships between all the agents in the system are complex, but ultimately, according to the propaganda model, mass media's incentives align with business and government incentives.