Well I parsed it as 'a white woman, who was visibly angry'. It is very clear from the context what the situation was, and the racial identification is crucial for the anecdote to make sense. This is a person who has likely been raised to believe (rightly) that racial segregation is a Bad Thing, and is failing to understand that minority groups may wish to have their own, positive, space. She therefore probably perceives this as perverse or hypocritical, and so is angry. So identifying her as a white woman who was angry is completely appropriate.