under which circumstances can someone even consider to call the recent Greek political system social, democratic or Social Democracy?
For one, they actually have elections; Quite a lot of them actually, apparently twice a year.
Secondly, they've had a left-wing social democratic party in power due to them winning these elections for a while now (
https://en.wikipedia.org/wiki/Syriza), who I can only imagine have been implementing some kind of left-wing nonsense the whole time.