Examination of the control column etc would certainly be helpful though I don't think this is the root cause but maybe a subsequently contributing cause.
So if the control column broke off at lift off or just after you don't think this would cause an accident? You are aware it was a single control aircraft?
Do you think any other Aircraft Accident Investigator in the developed world would dispose of these critical items without proper examination in such a major accident?
Why wasn't the control lock even found? It is plainly visible in the photos. Did they not know what it was?
The flight testing proves nothing in my opinion.
Hard to believe anyone could seriously think that.
Hopefully your opinion doesn't count for anything in this case.