I'm a Jew and had family and family friends die in that terror of Hitler's and his merry band, but I still have to acknowledge her capacity as a photographer. Look at her use of light and motion in Spear Thrower and again in Circle Dance. Can you honestly tell me that neither is great photography? No, she knew just how to use her tools in order to tell a story or let the viewer gain another viewpoint. I think she was one of the best photographers of that century and yes her ties to nazism were ill done on her part. Her movies were outstanding in their use of light and composition, regardless of the theme of them.
I'm not an apologist for Leni, rather I condemn the whole of the Rat Pack who took over Germany and also the "ordinary" people who let them do so. I don't feel she was any worse than the persons running the ammunitions factories or the clothing mills or the producers of aircraft during that time. What of the "ordinary" grocer, baker, farmer who did nothing to stop Hitler. I do think that one has to separate the abilities of the artist from his/her feelings and actions outside her/his art.
Peace, enjoy the beautiful of this world.