Book 6 does not treat love as decoration in the spirit world. Love is the actual medium of life there.
That means love is more than atmosphere. It is also transport. The chapter says people move, meet, and recognize in proportion to love. In other words, love is both what you breathe and what carries you.
This is a useful sermon image because it turns holiness away from abstraction. A person who never learned to breathe love on earth should not expect instant ease in a world where love is the air and the road at once.