That is something I personally struggle with. I find that much of the appeal towards moral relativism is that it sees the individual as the arbiter of their own personal moral values. However, this could be a problematic since there would be no reason to oppose someone who feels moved to impose their views onto others. Plus, I would say most people agree that causing harm to others is always wrong. However, we may have many disagreements about what is harmful, and in situations where causing harm is inevitable. Like the argument if it is okay to shoot a mass murderer in self defense if by not doing so you could be risking innocent lives. There are even moral complexities often addressed when to implement one good often means the sacrifice another good. For example, freedom and security are two goods, but in practice one is going to be sacrificed for the other. Then there is also the question of what to do with relative customs that vary. For example, in Slavic countries it is considered rude to smile at strangers, while in the USA it is percieved as being unfriendly. So then what standard is there to say that’s relative to other countries? So I would probably agree that it would be arrogant to judge one culture or individual solely by the standards of your culture or your own values. I remember reading in the inescapable love of God, that our ultimate will is identical with Gods will. Yet sometimes people can quickly appeals to “God said” often based on bad interpretations of scripture, such as people using Jeremiah 10:1-5 as reason for condemning Christmas trees, when such an interpretation is nothing more than some arbitrary legalism. Or I remember people saying about legalistic preachers that “Its convenient that God agrees with you on everything”.
As moral theories, moral relativism and moral absolutism are not collectively exhaustive. There is also moral hierarchalism as espoused by Norman Geisler. This is the view that moral imperatives can be arranged in a hierarchy such that some of them take precedence over others. For example saving someone’s life takes precedence over refraining from lying. Thus in this moral theory it would be morally right to lie in order to save a life.
However in moral absolutism, there is no morally right course to take when faced with such a moral dilemma. Refraining from saving a life where possible is morally wrong, and lying is morally wrong. Therefore which ever choice you make, you are doing something morally wrong. The best you can do is to choose the least of two morally wrong acts. Thus you might choose to lie in order to save a life, since lying would be less evil than not saving a life where possible. Yet, as a Christian moral absolutist, if you take that course, you will need to ask God’s forgiveness for having lied.