Speaking rechilus is prohibited even when it is made clear that the act committed was totally justified. It is therefore forbidden to tell someone that another person spoke negatively of him for a constructive purpose (l’toeles). Moreover, it is forbidden to tell someone that another person spoke negatively of him upon the advice of a posek (halachic authority). People tend to bear ill will towards those who speak against them even when it is obvious that the speaker was justified in doing so.