I don't know for sure in this case, but often airlines are reluctant to change stands at the last minute, even if offered alternatives by the airport. As a result if the preferred stand is occupied they can still end up holding for a while despite being surrounded by other possibilities.
Stands are at a premium around 7am when the nightstoppers are leaving and the longhauls are piling in, so the airport don't have the luxury of keeping a stand free for the hour before a flight is due in just in case it shows up early. A downside of that of course is that a delay to the previous flight can easily have an impact to the next one.
Not poor customer service, just commercial reality I would have thought.