I don't know about raping the German language but your friend is right in that a) Heideggerr, more than maybe any other philosopher ever, is harder to understand in translation and b) a Marxist might have a lot of trouble explaining Heidegger.

He definitely is not an author one should take on by oneself and I definitely can't explain much of anything he's said. I do lean toward the position that he said meaningful, even important things but thats totally based on people whose rationality and intelligence I trust regarding other philosophy telling me so. His obscurity is definitely the cause of a ton of bad philosophy.