LEV995 Chazal say that the pasuk: וְלֹ֤א תֹונוּ֙ אִ֣ישׁ אֶת־עֲמִיתֹ֔ו, “Do not distress a member of your nation” (Vayikra 25:17), refers only to someone who behaves like a member of your nation, by keeping the Torah and mitzvos. To such a person, one may not speak in a way that causes him distress. If one does not take the words of Hashem seriously, however, one may humiliate him by mentioning his wrongdoings, publicizing his vile actions, and degrading him. Chazal also say (Yoma 86b) that one should publicize the actions of fakers in order to prevent chillul Hashem (desecration of Hashem's Name) [which may occur if others mistakenly think that these people are righteous and consequently learn from their behavior]. If one already reproved the sinner but he did not mend his ways, then it is all the more permitted to expose him, reveal his sins publicly, and heap scorn on him until he improves his behavior, as the Rambam writes at the end of the sixth perek of Hilchos Dei’os. However, one must take care not to overlook the specific conditions that must be met in order for this heter to apply.