My loathing of him is largely based on the fact that he was, and remained until his death, an unrepentant, and even an enthusiastic, Nazi.  It's true that I also don't care for him as what I've read of his work strikes me as romantic and even mystical, when it is comprehensible.

For example, I thought his The Question of Technology to be at once dour and fanciful.  He seemed to be condemning the use of technology to generate energy through regulation of water, and its use to extract and store coal, declaring the former to be, in effect, monstrous and the latter to be a kind of rape of the earth.  The fact that humans have been regulating (altering its course at will) water through irrigation, and using it as a source of energy in milling, for thousands of years, and cutting and storing lumber as well for millenia, isn't mentioned in the essay.  Instead, a hydroelectric plant and mining through use of technology is compared, unfavorably, with peasants lovingly planting seeds in nature's bosom and such.  It's difficult to believe that this kind of reasoning is given serious consideration.  But that isn't grounds for revulsion, typically.

I've been scolded for this by several persons.  Usually, the scolder has (sometimes grudgingly) acknowledged his Nazi past, but considers it a kind of fluke or flirtation.  If so it was a long lasting one, as he didn't relinquish his membership in the Nazi party, and was a member until the end of WWII.  I've also been told that his philosophical work must be distinguished from the man himself, and that his philosophical work is superb, sublime; think of the most excessive expression of adulation you can conceive, and repeat it with his name as a sort of mantra, and you will begin to understand the praise he receives.  

But I think the attempt to distinguish the Nazi from his work is becoming more and more difficult as we learn more and more about him.

I've been listening to an audiobook version of Richard Wolin's Heidegger in Ruins:  Between Philosophy and Ideology.  If the claims made in it are accurate (and a persuasive case is made that they are, and that they're well documented), I think it is unreasonable for anyone, now, to claim that Heidegger the faithful Nazi is unrelated to Heidegger the philosopher.

This is because the publication of the so-called Black Notebooks has served to reveal the extent of his anti-Semitism and his acceptance of the mythos of Nazism (the superiority of the German Volk and its special mission to save the West, if not the entire world, from World Jewry and technology and attendant nihilism), and their relation to his focus on Being, even as it appears in his book which is given a kind of sacred, biblical status by his followers--Being and Time.  His nearly ecstatic reflections on German superiority and its mission seem not dissimilar to statements made by Himmler.  It seems that Heidegger thought the Jews if not every other people but the Germans lacked Being.  But for the Germans, all others have no connection with Blut und Boden, apparently a necessary condition of Being.

If this does not justify the war and the Holocaust, it seems to have sufficed as far as Heidegger was concerned to relieve the Germans of any blame for them.  Thus, he wrote of the "self-annihilation" of the Jews and the "inner truth and greatness" of National Socialism well after 1945.  His claims when rector at Freiberg (that's him posing as rector at the head of this post) that Hitler was the future of Germany and its law and similar hosannas to Der Fuhrer and his programs were not isolated, foolish statements, but expressions of strongly held beliefs.

I still have much to listen to, and will try to do so, though frankly the portrait of Heidegger appearing in the work so far is that of someone who was at best a disingenuous, self-important, poseur with looney, mystic beliefs in a master race and at worst a dishonest, self-serving apologist for mass-murder and a brutal autocracy.  It makes for disturbing listening.