Cruelty was one of the things that was most repugnant to Sri Aurobindo, but he always said that it was the distortion of an intensity, one could almost say the distortion of an intensity of love, something which is not satisfied with a middle course, which wants extremes — and that is justifiable.
I had always known that cruelty, like sadism, is a need for violent, extremely strong sensation, to penetrate a thick layer of tamas that feels nothing — tamas needs something extreme in order to be able to feel.
Ref: On Thoughts and Aphorisms