Remember? After Eve and Adam, who was with her, also ate of that tree, God later observed, "they" had become like "us", knowing good from evil. Which translates also to , right from wrong.
What then is the deeper message when God knows right from wrong, planted that very tree bearing the fruit that would bestow that knowledge on those who consumed it, and then cast out the first two people He created for then knowing those very things that would have allowed them to actually comprehend His prohibition in the first place; do not eat. Because they did not at first know how to obey God because they did not know obedience or disobedience so as to make an informed choice. They simply followed in innocence what they were told, and then were beguiled by a wiser spirit, the serpent, that was allowed to tempt them to disobey God, when they weren't consciously able to choose to obey or disobey before eating of that fruit.
Where is the message then?
Why is it wrong to become like God and know right from wrong, good from evil?