I think the problem for Molly is that, certainly at the beginning, she relied heavily on the happy home life they all had together as a family in the US -
http://www.thejournal.ie/molly-martens-corbett-children-2301841-Aug2015/ Her posts were filled with pictures from Jason's FB account to indicate that this was the life he had chosen for them all, how happy they all were. Her father referenced his many times golfing with Jason and how great their family life in the US was. It was in the beginning, when only custody was an issue and they chose to put forward the defense that Molly should retain custody of the children because that is what Jason chose for them.
It was only once details began to emerge of the violence that occurred on that night that the posts began to change, you can see the progression as time wore on and more decisions go against her, the level of thinly veiled anger increases consistently. Whether one could argue that this could also be true of an innocent who feels they are being perpetually wronged is another matter, but my point is simply that her very first posts indicate how willing the Martens were to manipulate the truth in order to achieve their goal from the beginning. They could have chosen to keep the whole affair private, but instead, given the knowledge they had of the level of violence inflicted that night, they chose to push their agenda from the very first moment of what 'fine people' they are in order to get what they wanted.