What Kind of people is that?

I wondering why there are some people in the world, (A) hiring someone (B)with the knowledge which he is lack of but still... don't believe in (B) capability and still questioning the background knowledge that people might have to spend thousand of hours to explain to him especially during exigency ? Why there are such an idiot people in the world? My advice to (A) is don't use (B), do it yourself! (A).