What does "vampiric" mean in this context? [closed]

Solution 1:

It's an extra emphasis on "intensity". Vampires are, after all, intense individuals.

I doubt you'll find a definition of "vampiric" anywhere that includes this; it's certainly an artistic flourish. It is augmented by the other-worldliness overlap that religious faith and the supernatural share.

Solution 2:

The metaphor seems much more complete than just emphasizing intensity.

Vampires are outcasts, alienated from the living because of their status. They linger at the fringe of living society and need to feed off that society to survive. They are both attracted to the living and despise or disdain them. They approach the living but are often rebuffed and sent reeling into the night or into an altered state (as a bat, a wolf).

The author is talking about the behavior of an atheist before he is reclaimed to the fold.

Like a vampire, the atheist is an outcast to believing society. However, the atheist is, in part, defined by that society, lingering at the edge (spent so long on the brink of faith), was attracted to the benefits of the believers (yearned for its emotional consolations) and was so intense, but fragile, that any challenge would drive them off (the slightest breeze would send them spinning into the abyss).

It is pretty graphic in its analogy.