Empathy is really quite a self involved process that is about self and not the other.
A significant attachment figure was never fully internalised in childhood and thus there is a sense of a hole inside self. The therapist is used by the client to fill that hole.
Of course big feelings do occur in childhood, sometimes many of them occur and many are not dealt with or resolved as the child cannot articulate its need to do so
Anger is a distancing emotion it pushes people apart. When people want distance in a relationship anger can be used to achieve this
I personally disagree with this. In my view humans are naturally communal beings and we need (are dependent) on others at least to some degree.