IMO, having been there, the silence is a result of a) not being really prepared to defend their faith because there is no consistency/logic to it, and 2) a very real fear that we ‘antis’ might be right and they would lose their ‘testimony’ of the LDS Church (and we are back to ‘the Church’ being primary - not Christ).
This isn’t meant as an attack in any way, it is just simply the way it is.
Quite honestly, it was very hard for me to break some of these habits when I first left the LDS church, to get rid of the paranoia to lose the fear that my then newfound CHRISTIAN faith wasn’t going to go away if I read something, to realize I had to be able to defend my faith and learn basic theology. I joke about it, it it is also very true - I went to Bible College to get my theology straight. My BA degree is Biblical Studies and Theology which is a result of my having to re-learn things after leaving Mormonism like basic definitions and how to really read the Bible in context.
Here’s an analogy which might somehow fit something.
For years I put off getting prescription bi-focals because I didn’t REALLY NEED them,and I could get by with WallyWorld reading glasses, which I wore at the end of my nose.
Well, financial demands shifted and now I have some very nice bi-focals.
But I’m having trouble breaking myself of the habit of wearing them down at the end of my nose and looking OVER the distance vision part.
The glasses are good, it’s me that’s messed up.