Doesn't it say in Revelation that in the end times, the dead will rise from their graves?
Anyway, I think the zombies are real thing is mostly propagated by sleazy survivalist businessmen trying to make a buck on seeds, and FEMA bureaucrats who are trying to be funny.
Those documents exist as they provide a way for the government to train people in real life situations such as disease outbreaks, breakdown in law and order along with other events associated with a zombie apocalypse. The thinking went that they were afraid that if the drill looked realistic that someone might confuse the drill for the real thing hence why they used an impossible to happen scenario that has all the different situations within it that can happen so they can train for any number of real life crisis without anyone being able to be confused into thinking the drill is an actual situation.
