I think he was saying it's not a deterrent from committing more crime, not that it's not a deterrent from going back to prison. Which is to say, it's not deterring what we want it to be deterring.
Even if that part is useful though there's no real reason to impugn the integrity of the people the GP references, and the reply does not tell us why we should find those people more likely to be prone to self-rationalization, which it needs to.
Even if that part is useful though there's no real reason to impugn the integrity of the people the GP references, and the reply does not tell us why we should find those people more likely to be prone to self-rationalization, which it needs to.