Greece has had problems with Communists before WWII, during the war -- most of the so-called 'freedom fighters' in Greece's 'Resistance' were Commies -- and then Communists almost took control of Greece after after the war. It was only thanks to a robust response by the Brits during the civil war that ensued which kept the country from falling into Stalin's hands.
Not excusing anything by Golden Dawn. Just saying I'd look for commies trying to play 'good guy' -- which is pretty fricken comical IMO.
From France through the Balkans to Greece these 'undergrounds' consisted mostly of commies working for Stalin. Tito & Yugoslavia is a prime example of commie resistance fighters.
(but they fought against 'fascism' so it was okay...yeah, riiiight, whatever)
The movie “Z” was made many years ago but has many
parallels.