Golden Dawn are a reaction to extreme leftism.
And the only thing worse than a reactionary movement is the movement that provoked the reaction in the first place.
Right now Greece needs an Augusto Pinochet to fix their problems and get them back on course as a nation. No one on the left will fix the probems that were created by the left.
And if Golden Dawn are scum then blame the scum who created the chaotic situation that allows a group like Golden Dawn to prosper and seize the opportunity presented by chaos.
Seems to me Golden Dawn is extremely Left, just with racism added in, just like the Nazis.