The difference is Abbott said Shorten was the "Dr Goebbels of the economy" and Dreyfus said that calling a scare campaign a "truth campaign" was using "Goebbelian cynicism". Goebbels is renowned for his propaganda, so in one case Dreyfus is saying the Coalition's creative use of language aligned to a strong contempt for the reality of a situation is similar to high-level indoctrinational propaganda.
In the other case, Abbott is calling Shorten "Dr Goebbels" because, um.... because he's a Nazi?
My interpretation was that Abbott called Shorten "the Goebbels of economic policy" because he's accusing Shorten of spreading high-level indoctrinational propaganda etc. as Goebbells did.