They did this throughout history. In exodus they saved a race of people from extinction ,they said we consume humans and moses soon was covering his face because it shown.
Vampires are aliens feeding off us if we die they have no more food source. They have control over the government and world. When we get tooo smart and too difficult becaause of our advances in tech, they destroy us and use natural disaters to repopulate advance civilizations so they can continue to use us aas food.