He doesn't think that. The claim is that stuck in a silo with no realistic prospect of review of the sentence and no chance of rehabilitation amounts to "inhuman and degrading" treatment.
I agree.
Sticking someone in a hole because we don't know what to do with them is not the mark of a civilised society.
If he is so very clearly a sociopath who should not be released, there's no danger in a periodic review because he won't be released.
If, however, he is not so clearly a sociopath, we need to have periodic reviews for the same reason that we don't have capital punishment - the justice system makes mistakes. And rectifying a mistake should not be the job of a partisan politician who is subject to the whims and desires of that morning's headlines.
All they have to do is say that he gets a parole hearing after the first 25 years and every 10 years thereafter. But that would rampant softy-liberalism, wouldn't it?