To be fair, there do seem to be some genuinely good deals on some routes. I was looking at CDG or LHR from ATH in early December or Late January because that's when the biggest discount is. There were plenty of seats in the region 45 Euro to 55 Euro (U class, Light). Usually there's nothing available for less than about 80 Euro in winter.

Price graph ATH-CDG, Aegean only, for December and January - from Google Flights (because it's actually a surpisingly good tool):