I understand why you are asking the questions you are. I myself do not like neutrality. When I'm in session I expect attunement so some emotional responsiveness. But remaining calm may not be a sign of being neutral, but rather of trying to be accepting. I don't know. I don't know what your therapist is like or the backstory.

Perhaps an example of a different situation might help. When a child falls and skins her knee and comes in crying, the mother tries to attune to the child to soothe her. This is usually by trying to calm the child down while at the same time recognizing that she is hurting. If the mother reacted by showing the same level of emotion as the child (i.e. screaming and crying), the child would feel intense distress, would not be able to return to baseline, and could be damaged if this were repeated enough.