By the time they got to JFK with the already messed about pax (delayed departure, then cancelled 24 hours, then delayed departure again, finally getting going after midnight, and finally diverting to JFK) it would have been about 0330.
BA178, a 747, departs JFK at 0800 for LHR, does it not ? This would have been an appropriate way to move the delayed and distressed passengers, at the expense of cancelling, or severely limiting, the load of those booked on this flight. BA is a regular in straightforward cancellation and reaccommodation. Yet it's decided instead to further grossly inconvenience passengers for whom no hotel accommodation was available (or possibly, nobody was around to organise it) because the statistics would show not one but two groups of delayed passengers.