I struggle to imagine beginning a take off with an aircraft out of trim becoming a reason for a crash. My time flying a Tiger Moth is limited, but I do not remember the trim being such that it could not be overcome by simply flying the plane, while you retrimmed it. The pilot's statement seems fuzzy to me.
Indeed, there but for the grace of god go I, and I have certainly had my share of self induced " 'should have checked that" moments, but happily none have been high risk OMG moments. In aeroplanes as simple as a Tiger Moth, there is little for a competent, current pilot to forget, that should raise the risk to that of accident before that pilot could make the required correction.
In my opinion, newer pilots who learn from these unhappy events, must first and foremost learn to fly the 'plane! Very few GA type cannot be flown for at least a brief time, safely, while horribly out of trim. That is primarily because most do not have a C of G range large enough to require enough trim to be able to make the control forces too high. It is the pilot's responsibility to learn to manage precise control while an aircraft is briefly out of trim, and retrim.