We are morally obligated to treat each other with love and respect. I could legally insult you and try to cause you emotional pain for the sake of pain, for example, but I morally care about doing right by you whether I agree with you or not. If I did do such dishonorable things, however, others would be right to speak up against me to warn others and try to dissuade me from doing it again, because that is what is needed to have a functioning society.