How does the provided text describe the act of slander and the seemingly paradoxical role of a slanderer?

Chapter 19 offers a complex view on slander. It describes the act as a powerful, physical impulse that is not easily contained, moving from the stomach to the throat and then flowing from the lips "with great satisfaction." However, it then presents a paradoxical argument, stating that a slanderer is a great benefactor. The text claims the slanderer helps the person they defame by pointing out their faults, thereby making them alert and averting future calamities. In a striking metaphor, it suggests that while others use soap to remove dirt, the slanderer "removes it with his tongue." This makes the slanderer "highly venerable" for undertaking this act, which ultimately leads to their own mental downfall for the sake of helping others.