Was the teacher white?
Daily Mail ran big photos of the teacher in yesterday's edition, including photos of her husband and small children. All of them have blue eyes, fair skin and blond hair.
However, she may have always inwardly identified as black, so... feelings are more important than biology and therefore she should be able to join any black teachers' organizations she wants to. To do any less would be bigotry and discrimination against the race queer. /s