If Golden Dawn didn't exist the extreme Left in Greece would need to invent them. It gives them an excuse to claim a sense of moral superiority - which they don't deserve.
Golden Dawn are just a mirror reflection of KKE and the extreme left in Greece. Whereas the idiots in Golden Dawn worship Hitler, there are many on the left in Greece who still have a place in their hearts for Stalin, Lenin or Mao.
The fact that Golden Dawn are a bunch of incompetent thugs who couldn't organise a shag in a brothel, shouldn't detract from the fact that the much larger and supposedly more 'respectable' Left of the Greek Communist Party and many in Syriza have their own fascist idols.
They deserve each other...