I'm not entirely sure what your criticism is. I'll take it as meaning 'isn't it just an arbitrary accident that the vampires happen to be more rational than humans, and not an intrinsic part of those characters?

I actually meant that "rationalist" is a label that doesn't make sense when applied to an entity that's already rational, but I'll admit my phrasing was confusing... probably because my attention was mainly focused on trying to make a joke about p-zombie vampires. ;-)