I've always thought mass media was a powerful political force that has a significant impact on the way democracies work; I think you're right, the media has a big effect on how people perceive the world around them. It's difficult to consider the US media, despite mergers and acquisitions, as any completely unified force, but when wielded as an ideological tool, I've always wondered how far can mass media control public opinions like that? I know there's no way to test it on a large scale in any purely scientific sense, but I'd think it's fairly significant. I also wonder how the internet and social media is affecting traditional mass media. Regardless, I think it comes as a natural response to peek/look/investigate at these revelations and reaffirm one's preexisting opinions about the issue, although I'd imagine that comes easier for some people than others.