I feel I ought to clarify some of my thoughts on this matter.
First, I don't think we should be trying to put our own veterans who may have taken part in atrocities in WWII on trial. In the heat of battle and war, bad and morally confused decisions are made. Even though Operation Keelhaul occurred after the war ended, it could be considered to be part of the war, a terrible thing, in its own right, though it was.
The point I am trying to make about pursuing people designated by some as "Nazi war criminals" is that any crimes they may have committed were done over 60 years ago. They almost certainly didn't think they were committing crimes that they would be punished for 60 years after the fact. Their cause was wrong and evil, I believe. But that fact does not make them evil in itself.
Leaving them alone is far more just than pursuing them
because they are NOT, in my opinion, the human devils some think them to be or, in fact, necessarily particularly wicked at all.
In my lifetime I have heard from a teacher, a co-worker, and a retired Army Colonel, stories of specific atrocities committed by our guys during and after the war.
1) My high school Latin teacher told us how his commanding officer told one of his men, who had just lost his best friend in battle to take a German prisoner out for a walk. What he meant was: "I'm giving you license to kill this German in cold blood." And that's exactly what happened.
2) A retired U.S. Army Colonel told me of his brother witnessing, during Operation Keelhaul, Russian deportees breaking the glass windows of the trains they were in with their heads and then cutting their own throats on the broken glass. He said his brother felt terrible about this. But what could he do to stop the deportation of these innocent people and their ghastly fate? (See any parallels here?)
3) A co-worker of mine who served in Japan in the USAF during the Korean War told me of a U.S. G.I. who befriended, if that's the word, a Japanese family of five after the war. For some reason the father of the family said something that offended him, and he proceeded to shoot the entire family. He was punished by receiving literally lowest form of reprimand from his commanding officer for committing this appalling quintuple murder, in other words, the mildest slap on the wrist.
My point is evil acts were committed by individuals on our side and their side. I am not defending the evil policies of mass murder of the Hitler regime. I can understand how some people still want revenge, although they say and may think it's justice. What the "Nazi-hunters" are doing is wrong, though, and they should cease and desist in committing the cruel and incredibly vindictive (and short-sighted) campaign they are on.
I hope this gets my point across a little better.