I'm not a fan of the term, or the books, but I think what it may be referring to, in my life anyway, is a lack of being seen and/or respected as a person, as a separate person, and that can "traumatize" a sense of self. The hurt, burned -- maybe for some folks, beat down -- self or sense of self FEELS traumatized, injured (at least mine does or can, once I finally "got in touch" with it).

Once a self is that hurt, beat down, or injured it can slink away, disappear, or get cut off. (My experience, anyway). Like I locked it away for safekeeping and then threw away the key, so I couldn't open it even if I tried or (stupidly, some part of me felt) wanted to. That way, nobody could see it and hurt it again -- so, in that way, I guess in my case it was related to emotional abuse as well.

But. . .here's the thing again -- my parents, my family COULD DO NO BETTER. I know that, most of the time, they were well-meaning, or as well-meaning as they could get (my father may not have had much in him).

Calling things neglect or abuse puts too much focus on the other person, in my opinion, and not on in getting in touch with the pain and/or the lost self hidden away somewhere.

Yes, when that hurt IS touched or triggered somehow, there is frequently anger, and why not? But that's another topic.