I think this conflates typically verbose academic/philosophical writing with German itself. Many great old philosophers came out of Germany, in a time where writing obtusely to make a point was in vogue (in English, too, not just German), so this may add to the perception of German philosophy needing to be contorted.

I've read refreshingly concise modern works in both and English and German and can assure you that style is the writer's fault, not the language's.