It is a fact that people across geographical and cultural boundaries believe in some sort of God. All civilizations have had a belief in the supernatural. The ontological argument is digging behind that belief to the question of why? Why is this belief seen in our world?
Let’s do an experiment. Let’s think of an original thought. Something that no one has ever thought before. Be imaginative. Let your mind work and think of a picture or event or scene. Try hard.
I’m not sure what you thought about, but this I know, it is nothing original. At best it is a combination of events, colors, shapes, and scenes in our world. For instance maybe you got outrageous and thought of a blue giraffe with the teeth of a crocodile. Or a robot shaped like a trashcan talking to you. As cool and imaginative as they might be they are not original. Instead they are simply a conglomerate of stuff that we all see. It might be an imaginative image, but it is still putting together what you have already interacted with. Even the complex machines that we use today are putting together technologies that we are discovering.