The Chofetz Chaim begins the laws of rechilus with some fundamental points. Good intentions do not remove a statement from the category of rechilus. If a statement can cause ill will it is forbidden, regardless of the speaker’s good intentions.
The Chofetz Chaim focuses on a common tactic used in arguments between husband and wife, child and parent or employee and employer. Often, people name a third party as supporting their opinion.
A wife tells her husband, “Even your sister agrees with me. She says I’m right.” A son tells his mother, “Even David’s mother says I’m right that boys my age should be allowed to drive.” An employee tells his boss, “You know, your friend Mr. Friedman told me that I’m worth a lot more than you’re paying me.”
Using another person’s opinion to bolster your case does not win arguments. Often it serves to infuriate the person with whom you are arguing. The employer who is underpaying his employee will not suddenly be won over to his employee’s way of thinking because his friend thinks that the man deserves a raise. The more likely response is, “What right does he have to interfere? What does he know about my business?” The mother whose son wants to drive will not suddenly change her mind based on another mother’s opinion. Her response most likely will be, “How dare she meddle in matters between myself and my child?”
Despite its ineffectiveness, people use this strategy for a simple reason. They feel that it strengthens their position by turning it into a majority opinion. The hope is that the opposing party will feel outnumbered and therefore capitulate.
But Halachah looks past the strategies to the end result, and it identifies this strategy as one that is likely to create ill will. And that is why it is forbidden.