In the days they spent together, Bai E would listen to Rose share things she had been privately taught by the people from Arbitration Place, as well as the characteristics of her unique "spiritless" constitution.
Spiritless individuals didn't lack souls, it was just that their Spiritual Bodies were not projected into higher-dimensional space, but fused with their physical bodies instead.
Therefore, for them, it was not that they couldn't sense the power of Spiritual Energy, but that they couldn't sense the Spiritual Energy from the outside world.
As for the energy within themselves… Could someone accustomed to their own strength really distinguish between Spiritual Energy and physical strength?