For me the obvious difference is that Diary of Anne Frank is not written by a Nazi.
And to be very clear, I am not suggesting that all white men are Nazis. I am not saying Twain was a Nazi. I am not offering an opinion on whether he was racist, just pointing out he was a white man writing from his own experiences.
I believe that is why mamalion wrote: I would rather students read Our Nig or Life of a Slave Girl for a perspective that isn’t so old fashionally crafted from white, male privilege.
ETA: Since it is impossible for me to believe you don’t see the difference I have to believe this is just one of your “provocative” and posts. I am looking for the clues. Help me out?