How do you come to that conclusion??
Because nebulous statements like "the Captain must have ultimate responsibility for the safety of the flight" implying therefore, that this was pilot error, are facile in the extreme. Now, the Erebus crash *was* due to pilot error, but for very specific reasons - not because the Captain failed in some ill-defined ultimate responsibility.
Mahon - with a level of arrogance that beggars belief - thought his own level of insight was superior to that of Chippindale, who he wrote off as an uneducated, concrete thinking militaristic individual with no insight into the intricacies and infrastructure of "computerised" navigation. Nothing could have been further from the truth. But making generalised statements like "the Captain has sole responsibility once the wheels have left the ground" as if they mean anything (which really, they don't) serve only to entrench the belief of the Mahon camp that those who would ascribe this to pilot error are nothing but a bunch of conservative reactionaries who don't understand modern aviation or teamwork.
Am I making any sense??