In recent decades, the reputation of the German philosopher Friedrich Nietzsche (1844-1900) has been largely rehabilitated despite the unfortunate events of 1933-1945. (In contrast, Francis Galton is today widely considered to be a progenitor of the Holocaust.)
Nietzsche’s popularity with the Nazis has been widely blamed upon mendacious editing by his sister and her anti-Semitic husband after the philosopher’s mental breakdown in 1888. In Nietzsche’s defense it is often pointed out that while perhaps he didn’t much like Jews (other than Spinoza), he really hated anti-Semites.
I think Nietzsche is respectable again today for several reasons:
First, he truly was super smart with lots of brilliant ideas.
Second, with his proto-Tom Wolfe prose style, he’s extremely readable for a German philosopher (think Kant, Hegel, Heidegger; Marx, a snarky bastard, throws in a lot of fun sarcasm in his prose but is still a pedant).
Third, Nietzsche’s thought is seen as corrosive of Christianity, so he is on Team Good. (To be precise, however, Nietzsche’s objection to Christianity was not that some Christians had owned slaves, but that a lot of Christians had been slaves. Christianity, to Nietzsche, was a contemptible “slave morality.”)
Fourth, here is a Tablet article by Guy Elgat about why Nietzsche appeals to the left:
And it is precisely Nietzsche’s view that our identities are contingent on this and other ways upon the historical conditions in which we find ourselves that has been especially appealing to thinkers on the left. Here the emphasis is put on what can be regarded as Nietzsche’s anti-essentialism; on the view, namely, that although our past greatly defines who we are, our values, our psychological abilities and even our feelings and emotions are not set in stone and fixed forever by our nature or our nurture, but are an accidental result of the interplay of various forces or powers, and are, as such, in principle contestable, reversible, open to revaluation and reinterpretation. If one is powerful enough, Nietzsche suggests, one can, like the lion depicted in his Thus Spoke Zarathustra, overthrow, at least to some extent, one’s tradition and its various thou shalts, create one’s own values, and thus become an autonomous free spirit, liberated from the shackles that have hitherto controlled one’s fate.
… Thus Foucault was greatly taken by Nietzsche’s emphasis on the historical nature of human existence and on how central notions of how we think about and relate to ourselves and others—notions such as sanity and madness, sexuality, normality and abnormality—are constructed by various social institutions at different times and under different conditions. … Derrida, on the other hand, found in Nietzsche philosophical arsenal that enabled him, for example, to destabilize long-standing and seemingly fixed hierarchical oppositions that informed Western thought, such as presence/absence, speech/writing, interiority/exteriority, and pure/impure, and thus influenced later theoreticians in their attempts to deconstruct race and gender identities and expose their fluidity and nonbinary nature.
On the other hand, Nietzsche’s preposterous hear-the-lamentations-of-their-women values sound like a John Milius screenplay or an alt-right Tweet: “Steppe barbarian. Nationalist, Fascist, Nudist Bodybuilder! Purification of world. Revolt of the damned. Destruction of the cities!”
But, at least, Nietzsche wasn’t an essentialist. That would be racist!