If it was that they'd unearthed a previously unknown war criminal, I'd totally agree.
But, from what I gleaned from the article, they're essentially re-writing the law, broadening the scope of their definitions of war crimes from back in the day, so that they can prosecute a bunch of people who were known to be just guards and lackeys, not leaders and killers.
To me, it kind of smacks of a governmental department grabbing at straws to keep itself relevant before these men all fade into oblivion.
The law used to bring this guy to trial was The Israeli Nazi and Nazi Collaborators (Punishment) Law of 1950 which was originally introduced with the principal purpose of prosecuting Jewish collaborators with the Nazis..
"What's this" you say? Jews who starved, manipulated and killed Jews in the camps?
"The concentration camp system owed its stability in no small way to a cadre of
kapos, who took over the daily operations of the camp, relieving the SS personnel. Thus, absolute power was ubiquitous. Without the delegation of power, the system of discipline and supervision would have promptly disintegrated. The rivalry over supervisory, administrative and warehouse functionary jobs was, for the SS, just a welcome opportunity to pit groups of prisoners against each other and keep them dependent. The normal prisoner, however, was at the mercy of a dual authority, the SS, who often hardly seemed to be at the camp, and the prisoner functionaries, who were always there."
—Eugen Kogon, concentration camp survivor
http://en.wikipedia.org/wiki/Kapo_(concentration_camp)