Maybe because "This is trauma?"

I don't know... if you had always been hurt and denied and suppressed and abandoned and then suddenly the person that had denied you (you) was suddenly more open to knowing, wouldn't you want to step forth into the light?

The good news is you can talk "aloud" to them (it doesn't matter if you are aware of "them" hearing you or not) and tell them you know they are there, they are important, they matter and you do want to know their stories, but you need them to go slowly and gently and it is going to take time.