The airport gives bigger airline better treatment and higher priority, since they're more "valuable" customers.  it is the same everywhere.
Airline takes less blame here, not much they really can do.
"The need to find a place to park that Air Emirates flight forced crews to move the two Air Transat planes to the airport taxiway, where they could be neither refuelled nor serviced. As a result, they ended up being among the last planes to be refuelled."