It is all too easy to blame the contractor (this may or may not be warranted !)
The trouble is - to negotiate the modern MAA airworthiness requirements needs good leadership and high quality people in liaison between the contractor and the MAA 'audit' team.
As I have said before - an absolutely airworthy aircraft can be grounded purely on very minor paperwork anomalies,we try to do our airworthiness reviews during scheduled servicing but the aircraft can still be delayed back into service.
As I have also previously posted - In the last 2 years I have changed many serviceable components purely because there is a very minor log card anomaly,but sometimes it is easier to change the component than seek deferment until a bigger servicing/servicing opportunity !
I have always suspected the grounding is a little more complex than simple un-airworthiness and that a different mix of 'personalities' might well have tackled this problem very differently !
I still very much doubt that all the gliders were unsafe to fly and if it was obvious to the 'top brass' that there was really a serious issue then a new fleet would have been the easiest course of action !
But of course a new fleet might well not have been part of whichever Agendas are being acted out !