In their book Relativism: Feet Firmly Planted in Mid-Air authors Francis J. Beckwith (who recently returned to the Catholic Church after spending around thirty years as an evangelical) and Gregory Koukl described moral relativism as "an intellectual urban legend."
Moral relativism has deceived the majority of Western society. Many who proclaim it have never thought to question it but have gone on believing it because it teaches them to do whatever feels good - which feels like a good way to live life. Others who practice relativism hit bottom and see how shallow their lives have become. Most people who hold a view of moral relativism were simply taught it - or caught it, like a virus. It came from bad example and bad logic. It It came from a false understanding of "tolerance." It came from the justification of sin.
Relativism is taught and lived as if it were true. In fact, it is a logical self-contradiction. Moral relativism teaches that morality is simply about values and opinions. Don't impose yours on me! People ask: "Who are you to judge my values?" But to make this judgment universally for all means that there is a moral law appliciable to everyone: "Thou shalt not impose one's morality on another" says the god of tolerance and relativism. But that absolute law refutes relativism. Relativism teaches there are NO absolute laws. But here is a law. Therefore relativism is a logical self-contradiction. People teach relativism as if it were true, passing it around like an... an...
...an intellectual urban legend!