racedo - I would encourage you to Google to read up on the Aegean - Olympic takeover / merger. I believe the rationale given was that Olympic was in such trouble that a refusal to permit integration with Aegean would have led to Olympic very likely ceasing to fly commercially in a substantial way.
I believe EU competition law permits merger of 2 companies with non-trivial market share when there is significant doubt as to whether one company is a going concern - a similiar logic prevailed with IAG / British Airways buying bmi. Aer Lingus seems to be in good health, showing no sign of major problems like bankruptcy so Ryanair is being denied permission to take over Aer Lingus. If Aer Lingus were to spend a few years losing a ton of money and looked like going bust, then MOL might get his way. Until then, MOL will have to just carry on with life.
I'm sure your buddies in Dublin will be able to stand on their own 2 feet when competing in Greece though