You think it's justice? I don't think so. But that's besides the point. Even if this was "justice," it's not worth it.
Where is the good in locking up an old man, indoctrinated at an age where anyone could have been? I can't think of anything good about it.
On top of that, it's 70 years after, when there is no more lesson to teach, and he can help out far more being around and talking. We could use this time to try to get others in the spotlight, who were like him, so they can talk about history. Now they will stay hidden.
What's the bad in doing it? Common. That's easy. A guy who should just be left alone to die, is instead being locked up, for the pleasure of other people. Now, he has to die alone in a cell. Not to mention the history we lose, that mentioned above.
That's bad.
Let's be real. We only lose in doing this. We don't gain anything.