What a number of us have tried to argue on this forum is that a visual approach, especially at SFO, may not be as simple as it appears.
They were not forced into accepting it, were they? They could have refused the visual. Knowing your limitations is fundamental to any critical Maneuver.
Obviously, a visual into SFO, is not something that a majority of crew thinks is unreasonably dangerous. If that was the case, fine.
It is up to the crews that are not comfortable pulling it off to refuse ATC's offer.
Besides, it's not as if accepting the visual was their last chance to correct this disaster. As things kept getting worse, the Asiana crew demonstrated a lack of corrective measures at several different points.
This wasn't a one-off error. This was a series of blunders.
Factors that may be relevant are: fatigue, mode confusion, inexperience on type, inexperience as trainer, vectors on final, language, CRM/HF aspects etc.
Pilot error may not be the
only thing here, yes. But even in this list a lot of the problems can be directly or indirectly attributed to pilot incompetence.