I would say this: I don't disagree that man has created gods, but not all gods are created. Why do we seek knowledge and understanding? Why are they such prized possessions that we would delude ourselves in their absence? If we are merely highly evolved animals, there is no reason why we would seek knowledge of anything other than where our next meal is coming from and how to best survive. But you've endowed knowledge and understanding with intrinsic value in and of themselves. Christianity answers this. It says that God has afflicted all men with a longing for wisdom and knowledge of the world we live in and it says that he had made himself known through his creation. We search for knowledge and understanding because God wants us to find him.