Perhaps they haven't continued to keep their silence. They had a police 'escort' when they left their house ... would the police be doing that if they were being entirely uncooperative?
Perhaps they have just decided not to say anything publicly. Which is their option. No matter what others think about their choices.
We can all speculate about what we would and wouldn't do in their situation. I hope that none of us ever needs to find out.
From articles that I read last night, they dont appear to be bad parents and were conducive to a decent family atmosphere for their family - often being seen on family bike rides together, for example. (Not only recently.)
(These comments are not aimed directly at your post, just jumping off your post

)