Looking at the town hall loonies and death panel rumors, I'm reminded of acquaintances from high school who were on watch for the AntiChrist.
Today it doesn't matter whether these conservative reactionaries actually believe that Barack Obama is the AntiChrist. What matters is many of them are from a religious culture where they've been primed to be on the watch for a charismatic leader who doesn't believe what they do, and who will lead others astray. The infrastructure, if you will, for their emotional and cultural response is already in position.
Rational argument and even discussion have no place in this equation. What matters is faith. A certainty that they are right and that others are mislead and damned.