The results of any traumatic experience, such as abuse, can only be resolved by experiencing, articulating, and judging every facet of the original experience within a process of careful therapeutic disclosure.
Sadism is not an infectious disease that strikes a person all of a sudden. It has a long prehistory in childhood and always originates in the desperate fantasies of a child who is searching for a way out of a hopeless situation.
Those children who are beaten will in turn give beatings, those who are intimidated will be intimidating, those who are humiliated will impose humiliation, and those whose souls are murdered will murder.
If it's very painful for you to criticize your friends - you're safe in doing it. But if you take the slightest pleasure in it, that's the time to hold your tongue.
Learning is a result of listening, which in turn leads to even better listening and attentiveness to the other person. In other words, to learn from the child, we must have empathy, and empathy grows as we learn.