A sane person would only eat something that would end up killing them under what circumstance? The desire was more powerful than the consequence!
For the sake of arguement, Adam and Eve were childlike creatures who walked around in the nuddy giving animals names. They only came to knowledge after the fruit had done it work. When we warn a child it oftens forgets or ignores the warning in pursuit of its immediate craving. They often fail to weigh up the pros and cons.
Clam Nitpicker