It has been said that if there is human freedom, then we are responsible for our

It has been said that if there is human freedom, then we are responsible for our actions. By this, it seems natural to suppose that "given that there is no human freedom (let's just suppose for the sake of argument) then it would follow that we are not responsible for our actions." But this seems an instance of what is called the "fallacy of denying the antecedent". Is this really an instance of the fallacy or is it an exemption to the case because personally I don't see any error in the form of the argument.

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