A person who doesn’t believe in religion being sworn in on a religious book is probably just annoyed. They’re not going to feel loyal to it.
Sworn statements as a whole are just entirely symbolic and don’t really guarantee loyalty or honesty, but if someone who doesn’t believe rejects a religious text that they disbelieve and instead choose something that has meaning and value to them, it’s better in the symbolic sense. A scientist swearing in on a scientific text that’s meaningful to them and that also addresses human morality makes as much sense and symbolically reflects their devotion to their mission as a Bible to a devout Christian.
Sworn statements as a whole are just entirely symbolic and don’t really guarantee loyalty or honesty, but if someone who doesn’t believe rejects a religious text that they disbelieve and instead choose something that has meaning and value to them, it’s better in the symbolic sense. A scientist swearing in on a scientific text that’s meaningful to them and that also addresses human morality makes as much sense and symbolically reflects their devotion to their mission as a Bible to a devout Christian.