A First Officer might not have ‘the right’, but s/he has many rights as a supportive crew member. Also, consider how these pilots are to become Captains, or indeed how current Captains made the transition.
cockney s, all of the ‘knowing’ is based on hindsight - outcome bias. All that we might know is what was said and to some extent what was done, and even based on that the events are a creation of our minds. Factual knowledge might have been taught, or refreshed during an approach briefing, but there is no guarantee that this knowledge will be call on in situations requiring many thoughtful activities.
The report discusses these aspects, but without knowing exactly what the crew saw and understood – as related by them, there cannot be any clear conclusion – other than perhaps that they 'did not know' and that both crew members did not act as expected. Thus the post-accident questions should consider why appropriate action was not taken – what were the contributing factors, or even why we should have such an expectation that the crew will always manage.
Most modern aircraft have compass comparators, did this aircraft have such a system, would it work in gyro mode. If not, then crew procedures should be strengthen when setting and cross-checking the gyro mode.
Aircraft with comparators pose similar problems as crew cross-checks; a disparity can be identified, but without a third reference then the erroneous system cannot be identified. Humans tend to give technology greater credence than verbal warnings, thus with an attention getting system alert a GA might have been flown and the problem resolved at a safe altitude, but not crosschecking the st-by compass during an ILS.