The crucial point about humor is that its enjoyment is dependent upon which side of the joke you are on.
Think back to the last time a group of people laughed at you for some reason, telling you in all sincerity, “It was just a joke!” They may have laughed because you did something foolish, or because your boss jokingly said, “If you don’t get that report in by tomorrow, I guess you are going to be taking a long vacation.” Initially, you may have laughed along so as not to seem like a bad sport. Somehow, though, when you are on the receiving end, the remark is not at all amusing. And sometimes, you may get the feeling that the joke contains at least a kernel of truth.
It is this point that the Chofetz Chaim addresses. To the person who, after speaking loshon hora, says, “I’m joking; come on, I didn’t mean it!” the Chofetz Chaim says, “It is not a joke!” The person’s feelings are hurt. His esteem has been lowered. Words have power even when they are presented as a “joke.” Therefore, if a joke is derogatory in any way, it is forbidden.
In this segment the Chofetz Chaim focuses, once again, on the effect of our words. If one recounts a story and does not mention names, but through other details the listener may come to identify the subject of the story, it is considered loshon hora. Even if the story contains no negative information, but will eventually cause the subject to appear in a bad light, it is still forbidden. Delayed-reaction destruction is also destruction.
As we study the laws of shmiras haloshon in all their detail, we see again and again that Hashem has great displeasure when His children are portrayed in a negative light. Through these laws Hashem is telling us: “All of you are My children; please treat each other with respect and sensitivity.”