What is the ruling on defending the honor of disbelievers?

Cursing, reviling, and slandering people's honor are not characteristic of a Muslim. The Prophet (peace and blessings be upon him) guided us to abandon cursing a Jew even if he deserved it, explaining that Allah dislikes obscenity. An unbeliever is in one of two situations: either he is warring against Muslims, in which case he has no sanctity, or he is a covenanter or a dhimmi, in which case his life, honor, and property are inviolable, and it is not permissible to transgress against him. As for one who defends the honor of an unbeliever, meaning he condemns someone who curses him unjustly, there is nothing wrong with that; rather, he is acting correctly.