Fox News != all tv news. Reproduce that study using, say, BBC News or Al Jazeera English (or even better BBC news and Al Jazeera English) and we'll talk.

Not saying those channels are perfect, but not all TV is created equal.

It's true that there is quite a variety but I'd venture to guess that most US TV news clusters closer to Fox than it would to BBC/AJE.

I think only part of the problem with mainstream TV news is inherent in the medium. There's a lot of effort put into making it infotainment.