Not as monumentally stupid as suggesting a deliberate act, but getting close.
A deliberate act would, from the descent profile, to be something that should be considered. Why is the possibility of suicide immediately discarded just because its an unpalatable scenario although very difficult to ascertain.
So you construe the fact that ATSB found all the bits in one place as conclusive of a serviceable flight control system and structural integrity? Big call.
Not really a big call at all. The ATSB stated :
Pre-impact flight control continuity was established and wing flaps[8] were assessed to have been extended but set at less than 10°[9] at the time of impact.
Its a 172 nothing complicated about it. All the control surfaces arrived at the point of impact and those control surfaces were attached by the necessary wires to the point at which they are controlled. If the flight controls were rigged incorrectly then it would have become apparent during the previous circuits with the instructor. Once again the final descent profile at high power suggests that a flight control problem would not be the main focus of the investigation. There is no precedent for a training aeroplane in the circuit to simply plummet to the ground at a high power and high RoD unless it is being made to do so.
This is a rumour network after all so what do you think (without being stupid of course),might have led to the accident Clinton?