Only under an overly broad definition of "preventable". In the context of this article, "preventable" means that the failure mode was foreseen and not accounted

Only under an overly broad definition of "preventable". In the context of this article, "preventable" means that the failure mode was foreseen and not accounted for in the design. If the failure mode had not been foreseen then the accident would not be preventable, because how can you protect against something you can't even imagine?