You are thinking too linearly. Because a word is used one way in one place does not mean it is used the same way everywhere else. Perhaps this why it doesn't make sense to you. Look at the context of the story. When Adam and Eve were created the whole creation of God was pronounced "very good". After the encounter with the wrong tree and the serpent they were blaming each other and blaming God. So much for paradise. It is not necessary to destroy creation by making it completely evil, just a bit of evil will do. We all live with a mixture of good and evil in our lives, our comfort zone. I look forward to the time when all traces of evil are removed from me. Have you ever looked into the face of absolute innocence?