People fail exams all the time, for a variety of reasons. Every now and then here on HN there is a big discussion on how job interviews shouldn't have whiteboard coding sessions.
Maybe she was such a person who can't do live whiteboard coding. Oral exams are something like that. Then the system is perhaps bad, but it doesn't sexism was the cause.
Also usually oral exams involve more than one interviewer.
And I think it is fascinatingly manipulative to frame it as "all female are kicked", if there was only one female to begin with.
(Note: it is of course possible that sexism was the cause, but it can't be inferred from the information given. BBC sure wants to suggest it, though)