The simplest explanation is that the ATSB is doing its level best not to rock the Boat, not the CASA boat, not the Departments Boat and especially not the Ministers Boat.
Nothing must be published that reflects poorly on Regulator, Department and by implication the Minister. This includes any comment on an operator which calls into question CASA regulation and oversight of the same.
To put that another way, until the ATR incident can be blamed on pilot error or unforseen weather nothing will be reported.
By way of example. the British Government ordered a review into the horrific conditions for the British wounded in the Crimean war of 1853 - 1856. Their finding was that it was all caused by the non arrival of a shipment of hay due to weather, so no ones fault of course.
You can already see that approach in ATSB incident reporting here:
21/12/2013 201312681 Incident No Port Macquarie Aerodrome NSW ATR - GIE Avions de Transport Regional ATR72-212A Air Transport High Capacity Passenger G CTAF During the landing in windy conditions, the aircraft bounced and the tail bumper struck the ground.
That is an example of justifying the conclusion in advance.