Much as I’ve defended them in this thread, really don’t think that Angel of Death is a damning criticism of Mengele. I think if you asked Slayer they’d say it wasn’t intended to be either. Far more of a ‘neutral observer’ aspect to it, like you say. From memory, I think Kerry King was interested in the period and wrote songs about it. When asked why he wasn’t more condemning he responded that he felt it was obvious that the Nazi regime was horrific and he didn’t feel like he needed to spell that out to people. That said, think the best thing you can say about some of the lyrics is that they are ill advised. Very much of the view that writing a song about Mengele that isn’t overtly critical does not make them a Nazi band though, particularly when their songs cover many other areas and themes.
The song that @Kallgeese talks about upthread - Crooked Cross - is more critical of the mindset of people that can ultimately lead to situations like Nazi Germany and can be viewed as more outright critical of Nazism than Angel of Death.
