You said: A rational deity ought to at least insure that the punishment fits the crime. So because one chick decided to take a bite of a forbidden apple, all later generations are condemned to die—in many cases, in great pain and suffering. Sorry, that's a disproportionate punishment and, as such, it offends the rational mind.
The punishment was announced prior to the "crime." The "chick" was forewarned as to what would happen. That's what happens when you are created in the image of God-- there are consequences. Whyy do you blame God for something He didn't do?