Honestly, I think that's a "cause"... a multiplier, if you will... Getting pounded by biased/opinion pieces without the time in between to figure out what is reality and what is opinion. I think that drives an actual further polarization... not just an impression of polarization...
In the past you could hear a story on the news, bring it to the dinner table and have Dad/Mom set you straight...
Now... not only do we not share dinners, but, the polarizing news/opinion is unrelenting...
Maybe?