I second what zoiecat said. It is a protective action done with good intent for the self, even though it may be experienced that way. What helps me with those kinds of parts is being curious and accepting. I "talk into the void" a lot with parts like this, just talking to them as though they are there and listening even when I don't have any sense of them at all. It seems to work somehow. But maybe not right away.
My T and I are doing this with some parts that are stonewalling a particular topic in therapy at the moment. We notice it, back off from the topic and talk about them as much as we can. Each time we know a tiny bit more, sense a tiny bit more. It is slow work but it has to be done with respect.