Many, like memphisbelle, seem quite happy at GB, and long may that remain the case. If they can prosper in their own right then so be it and anyone would wish them well.
The problem is that they are doing this prospering in the guise of BA. The average passenger thinks that they are flying with BA.
BA mismanagement seem hell bent on handing out the flying to franchises, subsiduaries and wet leases. Any group seeing their work handed elsewhere are inevitably going to object.
If GB can thrive operating as GB, then no one can complain, but if they thrive by appearing to be BA and at the expense of those working at BA, then they should'nt be surprised to get lots of negative comment and resentment.