Moral Relativism is a kind of thought that everyone should not judge others since they have their own morals or way of rule.
Some more subtle arguments are that of cavemen or sailors on the high seas. If the cavemen or the sailors violate the law from the “civilised world”, they should be pardon or forgiven since they are forced to submit themselves to the “savage rule of nature”.
Such philosophy is not justifiable since we still need to decide whether one thing is wrong or not. If Moral Relativism can be justified, then there are nothing that we can judge since nothing could be wrong.