When a person gets hit by a car and dies, who is to blame?
The car manufacturer? The person himself for crossing the street, ignoring the red pedastrian light?
The city council perhaps for not making it obvious enough there's a dangerous crossing?
Or is it the person behind the wheel who did not pay enough attention?
Is it the bartender who gave him one drink too many?
Is the inventor of alcohol to blame?
In other words: when something bad happens, it's not always clear who's fault it is.