Heidegger is clearly ruled out, not just for Nazism, but because he comes off at times as a pedant and a bully. Descartes and Leibniz are both sometimes referred to as incurable sneaks, etc.
I just received Cameron’s vote for Spinoza, Bergson, and Husserl. Not a bad list: all apparently good people. But Kant would be another frequent vote-getter. And I can’t imagine Aquinas was a bad guy.
The ancient Greeks should probably be ruled ineligible, just because they are so old that a patina of legend has grown up around them all.
But, oh yes… Plotinus was widely respected for his character, considered so scrupulously honest that many orphans were willed to his care by dying parents who knew him.
Or we could try it from another angle and ask about the least admirable human characters among the great philosophers. Heidegger must be near the top of the list. Schopenhauer was another worse-than-prickly sort, such as when he threw his maid down the steps for making too much noise.
Oh yes, Francis Bacon… Said to have performed tortures for the government during interrogations, and also said to have kept a 12-year-old boy toy close by his side much of the time. (Bacon’s mother reportedly “worried” about her son’s dealings with this boy.) I also heard a few other nasty stories about Bacon.
As for Giordano Bruno, he would have been loads of fun at a dinner party, but he must have been difficult. And as far as I know, no other philosopher was ever accused of murder. (Not that I think he did it, but still.)
It is often forgotten that some of the greatest artists and musicians, rulers and conquerors, philosophers and poets in history have been gay or bisexual. Same-sex love was one of the bases of the ancient Greek civilisation that produced such great thinkers as Socrates, Plato and Aristotle who laid the philosophical foundations of Western civilisation.