For what it's worth, my feelings on this subject are that it's an interesting topic, but somewhat overblown. I don't think, contra David Brooks and Tom Friedman, that's there's been a sudden increase in coarseness in American public discourse. We've always had our Joe Wilsons, Kanye Wests, and Serena Williamses. George W. Bush was regularly compared to Hitler by anti-war demonstrators. Bill Clinton was vilified as a murderous tyrant by the likes of Jerry Falwell. FDR was accused of stabbing America's soldiers in the back through his concessions to Stalin at Yalta. John McEnroe was a strutting ass on the tennis court long before it was fashionable.
What's different today, I think, is that the explosion in the number of news outlets in recent years has heightened the competition for market share. In the 1950s, the three news networks held to pretty high standards of journalism, but they also conspired to ignore some opinions they found unsavory. Today, news sources compete with each other by trying to find the most shocking stories out there. The kind of behavior that was once ignored is now highlighted. As I suggested on the PBS show, the percentage of jackasses in our society is probably constant over time, but this is a relatively good time to be a jackass if you like attention.