A rock opera seems rather bombastic and anathema for a punk rock band. So too may be having hits, as the American Idiot album (2004) had a few. Still, this title song rebels against what the band feels is a one-note media, trumpeting and parroting a version of America they reject: a redneck nation.
Concentration of media ownership is a political concern. This is when fewer and fewer corporations and/or individuals own media sources, such as print, broadcast, television and Internet sources. Big Media in the USA includes Disney, Viacom, Time Warner and the News Corporation.
The concern is that concentrated ownership reduces the diversity of news being delivered, and increases its bias. Minority opinions may not get aired. The content can become too tied to the interests of a few big advertising sponsors.
You can Google away, alas, for various reports and studies all clearly showing that concentration of media ownership is and is not a problem.
The decentralization of how we can receive our news now suggests, on a less rigorous and more personal level, that if we think mainstream media is biased, sources closer to our own views are mere mouse clicks away. A danger here is only getting content we already agree with, confirming our own biases. This is more challenging in dictator-led countries in which media concentration is severe, when media is the government.