Can’t really see the point you are trying to make geohoveuk. Let me see if I understand. The flights you want to book on are full so you think that BA is making loads of money, but they are saying they are not making money, so they must be mismanaging the revenue? I think you have to see the wider picture rather than just flights to/from HKG.
Do you not see that training “all” those additional crew is an investment? If there is a strike then many flights will be able to operate normally, saving money. Crews know that there are these people waiting in the wings to do the job, lessening the effect of a strike, therefore saving money. Its a kind of insurance policy, not only for now but in the future. That is sound business sense