My point was that we don't have either of the two biggest pieces of puzzle.
A flight data recorder reports what happened before the incident. A crash site reports what happened after the incident. With those two pieces investigators can create a recreation of the incident with immaculate detail, even for the most subtle things like one nut failing due to an unrated lubricant causing a rudder hardover (this actually happened)
He could have just been practicing landing at an alternate that was guaranteed to have emergency services. If it were some big conspiracy why would he make it as obvious as performing the super secret task on FS:X? Did he also do flights to other alternates?
I can't remember what flight it was but there was some crash in Asia that was suspected to be the result of a pilot suicide. He kept flipping the circuit breaker for the cockpit voice recorder or something like that and then the plane did a rudder hardover and crashed. The NTSB declared it a pilot suicide but the country it occurred in refused to dishonor the pilot post mortem. Another incident happened where a disgruntled FedEx or UPS employee flew jumpseat on a carrier flight then tried to murder the pilots mid flight to make it look like the plane crashed as an accident in order for his family to get life insurance. The pilots fought him off and the guy was arrested on the runway.