And why does it need to be compared to a religious belief? Why not just swearing on something impactful for him? It doesn't mean he is deifying Sagan. Why his he a clown again?
Because Carl Sagan can’t strike him down with a bolt of lightning or send him to hell, so it’s just an empty gesture. For a religious believer it isn’t.
Religious rituals are not just symbolic, they are real. Communion for example is not just a nice symbolic act, it’s as real as taking your medicine, and much more important if you’re Christian.