The first part I understand. I'll have to think about your second comment on a day when I am not working, as it has not occurred to me. I keep a conversation with threads to review, so I'll pop this in there.I'm not a Christian but find a certain truth here. It's the kind of truth that symbolizes reality in a form that can be taken literally but is really a teaching story. The truth I see is: at a time in the evolution leading to people, the first fully conscious humans are separated from animal ignorance by developing the sense of good and evil. Thus they departed from the easy existence of animal innocence. In this sense they "left the garden".
I take Paul here to mean: if people are fully aligned with the Divine, they know no sin, no good/evil, because their hearts are pure and their actions are also. As a round I know puts it, they "dance to the rhythm of God".