[AshamedCaptain]

Is not a question about good faith or not. He may be showing completely unintentional bias. But the point is that the oral one gives you a shitton more opportunities to play that bias. If you even try to say that the oral exam is just "a normal informal conversation" rather than something following a very strict protocol you might as well just give up any appearance of fairness. How much role bias would play on such a conversation is just outside the scale.