I think Walters' slight outburst unfortunate, he has unwaveringly followed a track that perhaps frustration has taken a toll. Even if he is wrong, his probing is exacting and thorough. Unless anyone can give the exact cause of the crash then no avenue should be left unexplored. Perhaps some could be more co-operative with him rather than taking the first oppurtunity they can to denigrate and obstruct his investigation. No theories on this crash put forward to date have been without holes. If all the facts are known then the best fit theory can be determined. Shouting down Walters' theory for ones own preferred version does not mean his is wrong, especially if there are other facts having gone unconsidered.
If ARS-6 was or was not fitted is still debatable regardless of who said it was not --there could have been an operational or other consideration as to why that information might have been withheld. For those of you with sufficient experience may have come across such cases where the Freedom of Information Act does not tread.