My opinion, for what it’s worth, is that Diana was flawed. But I think we’re all flawed, no one is perfect, least of all me!
On the other hand, Hitler and many of his minions, was totally, absolutely personified evil. His deeds were unspeakable, but somehow he never got his hands dirty, and so there were thousands of others who were inspired by him to perform unspeakably evil acts.
I’m not aware that Diana inspired others to perform unspeakably evil acts. She was flawed, imperfect, like the rest of us.