This decision uses the 'cruel and unusual' wording. It is a stretch, but it is the way the actual words of the Constitution are often stretched to cover a situation that was just about obviously not the intent of the Constitution.
"Cruel and unusual" is too vague IMO. Just another example in which the verbiage used by the Founding Fathers wasn't specific enough (what constitutes a "speedy" trial for example? going to trial in 2 months or 2 years?), leaving a hole as big as a Mac truck for liberal judges to drive through. Had they studied Hobbs (the nature of man), perhaps they wouldn't have been so idealistic and would have foreseen some of this and tightened up the language.