Franklin E. Zimring is an American criminologist, law professor, and the William G. Simon Professor of Law at the UC Berkeley School of Law... (wikipedia)
If the court does not invalidate penalties that are this extreme, it is telling the states, 'Anything goes.
At what point is the discretion in individual cases actually a pattern which has become a concrete rule and that rule violates the principle and the spirit of the law?
That may be the politically safest way to run a parole board, but the problem is that it is a manifest perversion of what the legal structure is set up to do.