I also think we cannot discount the ever-present just-signed-on-this-week/month Freeper who is actually a lib/dem (DUer?) plant come to stir up the pot. I'm not much on conspiracy/paranoia stuff, but I think it happens more than we might realize.
Yes, disruptors probably contributed some, as well as conservative newcomers. Big issues are gonna attract people.
The format of online forums also makes it easy to spout off with little consequence.
I think FR has been successful in part because the spouters are usually outnumbered by people who are thoughtful or at least disagree somewhat respectfully, because difficult people have either left or have been banned, and because there's always another thread you can go read instead of staying on the one that just pissed you off.
Subtlety in a plant is directly proportional to their success. I have long questioned your bonafides.