One can no longer deny Heidegger's relationship with National Socialism as a short-natured gaff. It seems to bug people because Heidegger was quite clearly a brilliant man whose thoughts were in some way a culmination of a pattern inquiry, etc. stretching back to Kant. Indeed, in many ways Heidegger remains an influential presence despite his association with the Nazis.
Anyway, recently I ran across a statement by another influential 20th century philosopher (Leo Strauss) that I found useful in describing Heidegger's thinking. Namely - to paraphrase - that Heidegger was more interested in being than human beings.