Maybe it isn't a case of taking FR too seriously, but those who take whatever their issue is, and make serious discussion about it difficult because their considered opinion is the only one that is right (in both senses of the word). Their issue may be important, but they take their role in it much too seriously. Those people lead me to avoid whole classes of threads.
And this certainly isn't the only place on the web where the Schiavo case really affected the discourse.It will be interesting to see what happens here over the next few weeks.
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.