I'm not sure if there's a way to increase civility in our public discourse, but if there is, I'm pretty sure it doesn't involve courageously attacking anonymous commenters on unnamed websites. Yet that's the path Dick Polman chooses.
It should be clear that using Internet commentary as an indicator of declining civility is methodologically problematic. As I've mentioned previously, I take the percentage of jerks in society to be a relative constant over time. I am entirely confident that there were people who celebrated the death of John F. Kennedy and who rejoiced when Ronald Reagan was shot. Surely there were those who danced upon learning of Abraham Lincoln's assassination. But those folks didn't write comments about it on websites, for obvious reasons.
Of course, one difference, other than the lack of an Internet, was that mid-20th century newspaper editors and TV news producers felt it was inappropriate to air certain views deemed too extreme or incendiary. If you wanted to go public with a comment about how great it was that JFK got shot, there weren't many places for you to do so. Of course, people who want to write stuff today about how great it is that Teddy Kennedy died still don't have a huge forum -- they mostly write anonymous comments on random websites. These views don't get much of a public airing until, you know, syndicated columnists like Dick Polman choose to repeat them.