maybe they do it on the basis of how much they get paid per aircraft
All service providers at the airport (whether it be catering, fuelling, cleaning, de-icing, baggage handling, PRM assistance) prioritise airlines in order of who shouts the loudest, which is why the likes Singapore, Emirates, Etihad, Qatar etc very rarely get service delays compared to those airlines with no management staff on station.
It's much easier to delay an Air Transat and send a 'sorry' email then have to deal with 5+ Emirates managers hassling you over the phone and face to face in the next meeting