Two voices:
1: "Hard core Nazi, not someone to be admired."
She has long been rumoured to have been the mistress of a top Nazi (probably not Goebbels). She was not, in that regard, small fry. With our libel laws such as they are, no one would publish details about that aspect of her life while she was alive. But the dead can't sue for libel, so perhaps more will emerge now. Schwarzkopf, like Boehm, actively associated herself with those vile people.
2:Elisabeth Schwarzkopf was no more responsible for what the Nazis did in the war than any other musician or singer in Germany or Axis occupied Europe, who joined the party or not. Karajan joined twice for some reason. Karl Boehm's politics and compliance remain a mistery to some extent. Clemmens Krauss certainly held Nazi views. For small fry, as Scharzfopf was in the Nazi era, joining the party ensured one got a job rather than not. Maybe this is not very brave, but it hardly qualifies her as a hard core Nazi, or do you know more about her activities in that time than has generally been published.
I am not even sure I would regard party membership as even being controvercial, for a junior and up and coming singer. If you are famous then you can get along without joining up of course, very much as Furtwangler did, and even writing open letters to the High Command criticising their policies, but that did not stop him being branded a Nazi conductor for all that, but what on earth does it mean? Interestingly Furtwangler seemed to find an uneasy truce with the Nazi leadership after he was sacked as chief conductor of the BPO for advocating degenerate (their word not mine) music, and trying to keep his Jewish musicians in place. Naturally by 1935 they had also left the Orchestra, for all that...