How so? Most americans have unfiltered access to the internet where they can get far more information than the old days of having 1 or 2 local newspapers and 3 TV broadcast networks.
I agree that some people, us included, are saavy enough to read news sources from around the world and make reasonably informed decisions based on a variety of sources.
However, the US corporate news is largely a propaganda machine and the vast majority of US citizens get their news in propaganda form.
Don't believe that? Do an experiment: identify a few news stories on Fox News, MSNBC, etc. and then spend some some on Google News reading coverage for these stories from a variety of other countries. I do this a few times a month for news that I am interested in, and it is an eye opening experience.
The authors of "Dollarocracy: How the Money and Media Election Complex is Destroying America" spoke at Google last fall when I was consulting there. They roast local and national news as being very biased and not covering things that people really should know.