Why would you think this person is associate with FR?
Checking the article, the targets of his attacks were absolutely in line with the preferred enemies of readers of this list ("liberal" reporters, celebrities, and politicians). His politics apparently were very much in line with those here, although his tactics were obviously reprehensible.
Checking the other, much larger thread on this topic (already linked above), it appears that it's been confirmed that he was a member (now suspended). Apparently, he often posted in Katherine Harris threads, although I suspect he also had a few laughs from any threads on the fake anthrax letters.
Obviously, that doesn't mean that everyone here is a terrorist like this guy. But it might be a good idea for people to tone down the vicious rhetoric about what they'd like to see done to those that disagree with them.