Smilin ed
The operative word is "obvious". I would be more concerned if a major and definitive cause was apparent such as gross negligence in an SOP for instance. I do find it reassuring that so much has been ruled out!
I do take your point, however, that until a specific cause is found then there is always going to be a doubt. It may be a computer fault, maybe not (I would be somewhat anxious on a 777 flight fearing that the flight crew had just seen the blue screen of death on their displays just as the undercarriage was lowered.) Maybe a fuel contamination or freezing, maybe not. I beleive that the Accident investigation people know thier job and will track down the probable if not definitive cause.