Being German and trying to accept this aspect of German identity as a responsibility, it is not easy for me to contribute to this string. However, here are my thoughts: Riefenstahl was, for all I can see, able to create great pictures. Being an Anthropologist by education, I have admired for a long time her pictures of the Nuba. I am aware of the critique that she re-created the same aesthetics, a celebration of physical strength and alertness, thought to be also a Nazi ideal, which she did in her Olympics pictures, but personally i don't think this critique really holds water (though my own efforts to engage with another cultural context are very different, see my website below, the gallery "mystical Islam"). For me, the Nuba pictures show an effort of a real engagement and a respect for another people, and I respect that.
In the Third Reich, Leni Riefenstahl uncritically allowed herself to be made use of her talent, and to thrive on her political connections. Later she admitted she was misled, but she also played her enthusiasm down. It is difficult to throw the first stone here, and difficult, also for me, even though I have been told much by my parents and grand parents, and read on the subject, to really imagine what the feeling of life is when one lives through such a time. Easy to say one should resist, leave the country - where, for most people? Knowledge of foreign languages was not common then, people had families, children, employment. You have only one life to live... But on the other hand, there were people who resisted, who either left when they were famous or rich enough, or tried to make secret or half-open stances against official views, very dangerous at the time, even really lived through the daily hell of being humiliated, bullied, maybe incarcerated, tortured and killed.
For me, this is an open question, maybe not at all resolvable once and for all, really a question about the nature of evil, and human fallibility.
For a comparative note: since long time, I think that the idea of the uniqueness of the German disaster is misconceived (not because I would want to diminish it), and that there were two great catastrophes in the middle of the 20th century alone, instigated by Hitler and Stalin. Now, I admire Sergej Eisenstein's films which were certainly politically correct, but still more I like Michail Bulgakow's novel "The Master and Margerita", not politically correct at all, and published only posthumously.
In Germany, it was the luck and the chance of people like Guenter Grass to wake up when they were young, to look around and perceive the disaster, and to go on and lead a free life, and it is his lasting merit to have shown to Germany, and the world, the power of temptation, the subtle seduction of ordinary people. In Russia, people had no such chance. Solshenizyn tried the same for his country, perhaps not with quite the same talent, but he was bullied a lifetime, had to go into exile - and he is lucky to have got out!