. I believe the pilots were highly experienced and very competent, so pilot error must be a very very remote possibility!
As aircraft accident statistics show competency and experience has nothing to do with it. Take some most egregious cases of pilot error (in commercial flying) in the last say 40 years and they were all caused by experienced and well trained crews.
However I think the pilots had more instrument approaches under their belts than visual approaches and it is baffling how a localiser approach could be so badly stuffed up?
Not sure what it is supposed to mean, approaches in IMC weather are flown in minority of cases, say 10-20% (will depend on geographical area) so visual approaches tend to dominate in pilot's logbook.