Why was Blackbeard trying to kill the fairies?

What sort of logic is that? We see that he needs the fairy dust to live, we are told he made them go nearly extinct once before aside from this hidden group of fairies, we saw him mining for small bits of crystallized fairy dust to stay alive, and his first thought is to kill the creatures that make the stuff? Again!!!? It makes no goddamn sense as far as I can tell.