Vampires are predators and parasites. They kill whomever they feed on. They don't respect a human's right to live. But no vampire wants all their prey to just suddenly all die and be gone. The object isn't to just kill people. Vampires know that if you kill all of the people, then vampires will also die. This makes vampires, who are monsters, better than the average gazillionaire.
@nevikjames Neither do gazillionaires, hypothetically