just before takeoff
Perhaps, just perhaps, the Captain was preoccupied whilst the cabin had been secured, all passengers and cabin crew strapped in, take-off imminent, perhaps a slot time to make, an on-the-spot discretionary decision by the cabin crew member to expedite departure and not inconvenience hundreds of passengers for an explanation that some might find extraordinary, perhaps even alcohol or narcotic induced.
I despise that the industry has been reduced to call centre type mentalities wearing brightly coloured tee shirts but there is no suggestion of that being a factor in this situation.
As for providing a service for the passengers that pay their wages, it is well known regarding restricted if any mobile phone usage on board airliners and if that is a problem then take the bus or the train instead.