Indeed a society which followed determinism wouldnt believe a criminal to be guilty because of course they have no free will over their actions. In fact everyone would be free of blame and guilt. In the same way everyone would be free of achievement. Yes that would be a bad place.
But couldn't we just live with the knowledge of Determinism being truth and at the same time understand that we must force ourselves to live under the rules of free will for our society to exist properly?
If determinism was proven true it would be stupid to simply ignore the fact as much could be learnt from such an insight. As long as we accepted that such a truth shouldnt interfere with our society and that life must go on as before with all its guilt and blame our society wouldnt suffer at all.
That is why I believe in determinism but at the same time I will never use it as an excuse for my actions or anyone elses (even if it is proven).