Read any good books lately?
I chalk it up sometimes to disrupters. A person who post the same rant 3 times inside the first dozen posts. Sometimes these people never return to the thread; their work is done as most people reading will be so outraged by what they've said that they feel they must respond.
Other times, they pick around the edges of an argument and never respond to posters' rebuttals even though they stay with a thread. Again, a single disrupter can derail an argument.
After awhile, some of the names keep coming up with this tactic. You can check some of the other threads a person has posted on to see how often they hold to this tactic.
Some of the other disrupters will post a democrat site sourced article or other editorial never to voice in on the thread. Some of the threads will run to a hundred responses without a single followup post by the poster. When they remain active posters, it is a suspicious act (tying up system resources and the time of those who are responding).
Certainly we can always find something to chime in on here on FR and some threads do nothing but provoke outrage.