Can you conclude that the mental state was irrelevant? You can't. No, but you can’t claim it was relevant either. So either scenario is likely, so we rely on

Can you conclude that the mental state was irrelevant? You can't. No, but you can’t claim it was relevant either. So either scenario is likely, so we rely on the experts at NTSB to make a call. Saying “we cant prove its not relevant” is not actionable information, so it’s not really worth raising it.