As an aside to this, I think this has proliferated in the the internet age and we're just catching up with it. News isn't that profitable; fake news, which exploits people's fear and hatred is as explained in this Washington Post article.
There’s a simple, economic explanation for this shift: If you’re a hoaxer, it’s more profitable... Paul Horner, the proprietor of Nbc.com.co and a string of other very profitable fake-news sites, once told me he specifically tries to invent stories that will provoke strong reactions in middle-aged conservatives. They share a lot on Facebook, he explained; they’re the ideal audience.
This is what gets people clicking, this is what sells, this is what makes money, so this is the content that people create.
It was frustrating in the Tabloid days that the exploitative media sold more than the more intellectual, factual media but it's never been more destructive, prolific or completely free of regulation than it is now.
The ultra-commercialisation of information means that the most extreme content is the most profitable and widespread. And that keeps driving extremism.