ADL calls it "legitimate historical scholarship"

https://en.wikipedia.org/wiki/Arno_J._Mayer

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the Anti-Defamation League from including Mayer in its 1993 "Hitler's Apologists: The Anti-Semitic Propaganda of Holocaust Revisionism", where his work is cited as an example of "legitimate historical scholarship which relativizes the genocide of the Jews."
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Mayer had concluded as follows: "certainly at Auschwitz, but probably overall, more Jews were killed by so-called 'natural' causes than by 'unnatural' ones."
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