Bloodsucking Fiends/Fridge

Fridge Logic: How come neither Tommy or Jody figured out how to turn people into vampires in Bloodsucking Fiends: A Love Story? Tommy practically saturated himself in vampire lore that explained how the whole "biting and giving blood" thing works, not to mention that the method in the book wasn't even a subversion.
 * Even if they had come across that particular creation method... "OK Jody, here's what we're going to do: I'll drink some of your blood, and then you murder me. Let's see if this works!"
 * You'd think that the author, being Christopher Moore and all, would have at least Lampshaded that if it was the case.