That might be a result of where we live. I'm surrounded by a black county but live within a much smaller, isolated white left wing town. I see blind left wing partisanship everywhere here.I suggest we differentiate between (1) those willing to use technology to do their own self-informing vs. (2) sheeple who simply eat what they're fed.I disagree with the result. Instead of people being more informed (that would require effort) they are more easily brainwashed and conditioned by the intensity and immediacy of electronic media. Brainwashers on the left have dominated media and have succeeded the most with the brainwashing.The polarization has always been there.
The difference between today and 30 (or 200) years ago is, I believe, the scope or scale of the polarization.
An unanticipated outcome of the invention of radio and TV and cable and the Internet and smart-phones and tablets and lions and tigers and bears, oh my.
More informed people = more broad-scale intensity of opinion, as well as diversity of opinion.
I see things trending towards (1), while you appear to see the residual and modest dominance of (2) as remaining operative over the long haul.