Not to mention, according to that legend a third party (who would also be a creation of the same God who made them) told Eve it would be fine. So in her innocent/naive state, how is she expected to understand that it's a bad idea at all?
Of course the whole story wasn't about what reasonable people (or a reasonable god) would do. It was, like the Japanese Inugazi/Isunami story, a "just so" story of how the whole birth/death cycle got going, with a few additional lessons like why we're not immortal, why women suffer during childbirth, why you should defer to priests as god's stand-ins, etc.