There's every reason to wonder why a de jure life sentence couldn't have been passed instead of a de facto one. But to impugn the German legal system's determination seems to me to be barking up the wrong tree - at least in this case, where German courts made every effort to bring Demjanjuk to justice (the fact that such determination may have been lacking in many other cases involving German citizens is another matter). Dividing the years of his sentence by the number of victims would produce an unsatisfactory result in any case - That, Mr. Segev, is just cheap rhetoric.
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)
from the article: Tom Segev / Demjanjuk's five-year sentence isn't worthy of praise