It is sad that some will get offended over a possible cause of a crash and act if they are possibly insulted. Causes get dismissed as being highly unlikely over other possibilities. First off.... your feelings don't matter in an investigation. The FBI conducts a criminal investigation along side the NTSB to rule out the possibility of foul play. Should they care that you or anyone else might get offended at the possibility that criminal activity caused the crash? No. They shouldn't. Nor should anyone else. Let's step down off of hour high horse and use a little common sense. How many criminal acts in the cockpit (just because of the pilots of a crew member/jump seat) have brought down a plane versus any other single cause? You know what? A criminal act in the cockpit is more likely the cause of a crash than a pitot tube bringing down a flight at cruising altitude. Also more likely than fuel contamination bringing down a flight at the end of the runway. More likely than the roof of a plane getting ripped off mid flight. All of those other causes are far less likely than a criminal act. Doesn't mean that a criminal act caused this. It is just ignorant and arrogant to be dismissive of that possibility because you get your feelings hurt or want to defend a legacy. What about that good man (and I mean that seriously) that had a mental break, stole a commercial plane, took it for a joyride and killed himself. Most ridiculous scenario ever but it happened. People have mental breaks that cause them to do things no sane person would ever do. Sorry but criminal acts are every bit as likely (or more) to cause a crash than any other single cause.
No one is suggesting the NTSB (and FBI) shouldn’t be investigating every possible avenue, including an intentional act. What is being suggested is that throwing around theories willy nilly with zero evidence beyond “we can see the aircraft entered a dive and impacted the ground” is not going to really get anywhere other than idle speculation, and ends up in dozens of pages of inanity which buries any actual informed comment. When I first saw this thread, it was already 7 pages long, and it was only that I happened to have a good chunk of time that I bothered to read it.
If someone is positively suggesting this was a deliberate act by flight crew (hint: this is something not done by competent investigating agencies in the first weeks of an investigation unless there is clear evidence such as in the Horizon example you cite) as opposed to pointing out that at this stage nothing has been ruled out (hint: this is something that is done by competent investigating agencies in the first weeks of an investigation), then all they are doing is throwing around baseless accusations. Given this forum is read by 1) colleagues and friends of the deceased pilots and 2) journalists looking for a new angle, I would suggest baseless accusations are not as harmless as being made out. You wouldn’t be too happy if you became an in active poster for six months and I began suggesting one possible scenario is that you have been arrested for possessing illegal material on your computer (even though that theory would fit with the available evidence).
Unless you are investigating this accident yourself, I would humbly suggest it is you who needs to step down of your high horse, and allow the professional investigators to do their work. When there is a premimary factual report in a month’s time, then there will be something to discuss and make some informed
speculation on. Pretty much everything before that is just noise.