My Princeton education helped fill me in on what really happened. One of Nietzsche's best translators, Walter Kaufmann, my teacher at Princeton, made a career out of fighting the Nazis, plus check out this quote from Nietzsche's own Twilight of the Idols:
One pays heavily for coming to power: power makes stupid. The Germans -- once they were called the people of thinkers: do they think at all today? The Germans are now bored with the spirit, the Germans now mistrust the spirit; politics swallows up all serious concern for really spiritual matters. Deutschland, Deutschland uber alles -- I fear that was the end of German philosophy. Very prescient (we're talking like 1888). Lots of parallels to our own time.
Kaufmann was adamant that we ought not waste time reading Heidegger, given he'd sold out when it counted. You should judge a philosophy by the character of the philosopher, was his message.
Since WWII, from such histories as War Against the Weak, we've learned a lot about where Hitler did get much of his conceptual ammo: from North American eugenicists, many of them establishment types. 
The best we can say of 20th century philosophy is we're still here in the 21st, and becoming more viable. That's not really high praise though -- closer to "minimum acceptable." Academics are still pretty spineless, even today, especially those so-called philosophers (we've not had many of Kaufmann's caliber -- too much inbreeding I suppose (in a memetic sense, not talking genetics)).
Anyway, I'm glad we're overcoming at last (long overdue).
 Walter Kaufmann, The Portable Nietzsche, Penguin Books reprint, 1977, page 506.
 very lame to go after the Bush family on this however, as Kitty Kelly makes clear after checking into it more thoroughly