If free will does not exist, then it is ultimately not anybody's fault if they do something. That includes murder and buying cigarettes. But at the same time it is easy to see that as a society it is advantageous for us to punish criminals because that punishment is part of the environment that influences behavior for criminals and non-criminals in a positive direction.
So - nobody is responsible for any action, but it is useful to pretend they are.
Another reason why the concept of free will is so ingrained in western culture is the role it plays in religion - being saved/forever damned makes no sense without it. But like much of religion it is just an untruth that has (at least historically) proved useful for people. Since religion is so important to many people, they will also hold on to the idea of free will because understanding reality in a more accurate way wil undermine their religion.
So - nobody is responsible for any action, but it is useful to pretend they are.
Another reason why the concept of free will is so ingrained in western culture is the role it plays in religion - being saved/forever damned makes no sense without it. But like much of religion it is just an untruth that has (at least historically) proved useful for people. Since religion is so important to many people, they will also hold on to the idea of free will because understanding reality in a more accurate way wil undermine their religion.