Psiberzerker
Author
Ok, how about Elenwen? Eugenic torturer, do you think if she openly, and honestly apologized to Ulfric he would magnanimously forgive her, or seek "Justice?"Who Mengele is hardly matters, all that was implied by you was that he was a Nazi. Justice isn't killing people to show killing is wrong, mercy and compassion are far more important than justice or revenge. Also, saying Paarthurnax committed the same crimes is you assuming things. All that's stated is that he helped Alduin. It's been thousands of years since the Dragon Wars, and Paarthurnax has never left the summit of the mountain. He's stayed true to his way, he's reformed, and has devoted his life to peace, and finally defeating Alduin once and for all. After guiding the Dovahkiin through this path, he returns to Akavir.
Tell you what, Ask Paarthurnax. He won't tell you in any great detail what he did, but is fairly open about whether he deserves to die for it. I'll assume you didn't kill him yet, so you can have that conversation any time. I can't think of a more reliable source in this instance.