I haven't taken a position on this matter yet, but is anyone (credible) looking into whether the hype around this story was generated on purpose as an attempt to smear American Muslims? See:

The Radical "Muslim" Group That Threatened South Park Creators Was Founded and Run by Joseph Cohen, a Former Israeli Radical Who Used to Live in a Settlement in the West Bank http://www.reddit.com/r/worldnews/comments/bvnsa/