The problem, which various people have pointed out, is that this implies an intelligence capable of taking over the world, but not capable of working out that when a human says pursue a certain goal, they would not want this goal to be pursued in a way that leads to the destruction of the world.

The entity providing the goals for the AI wouldn't have to be a human, it might instead be a corporation. A reasonable goal for such an AI might be to 'maximize shareholder value'. The shareholders are not humans either, and what they value is only money.