Well, the point is not necessarily that it can be reversed. The point is that society takes the stand that taking a human life, no matter how debased, is barbarous. Of course, this takes us to euthanasia and abortion territory, so we could modify this by saying that taking a human life without a deathwhish and consent is barbarous - just as prolonging life beyond a certain point.

A good example of a candidate for life imprisonment is a mass murderer who has obviously shot tens of peoples without any remorse and boasts doing it again. The crime is not debatable - the question then remains - how should a society respond to such a situation.