"OK then, they can let Norwegian go bust. Booked passengers will lose their money, staff will lose their jobs. Well done officials."
They are concerned with COMPETITION - they can/will make IAG divest itself of slots, routes, aircraft. The aim is to avoid monopolies
It is no co-incidence that air fares across the Atlantic are (relatively) high - 80% of flights offered are from one of the "Alliances"