Reading defenses of religion, I often encounter the complaint that the modern, secular world is caught up in moral relativism. What we need, however, are moral absolutes. We have to have a secure direction by which to orient our lives. Monotheistic religion is attractive to such moral absolutists, because conservative monotheism proclaims absolutes. It may do so in the form of divine law, but it also presents ideals such as stories of saintsimages of lives oriented toward an unshakable pole of righteousness. Therefore we must have religion; otherwise we are lost.
This is not, I think, really an argument. There is an element of complaint in it. After all, secular modernity does not sit well with every temperament. And there is also an element of observation. Moral absolutists correctly observe that, especially in today’s fluid modernity, most of us have to live lives where acknowledging a pole of righteousness is very difficult. Whatever anyone’s private convictions, moral relativism appears to be socially established. A modern, secular person can try to live a saintly life, but just what saintliness consists of is very unclear. The idea might not make sense anymore. And even if a secular person selflessly devotes themselves to a moral cause, it would be hard for them to achieve the serenity and certainty associated with a saintly ideal. In the secular modern world, doubt infects everything.
So, perhaps, moral absolutists are really declaring that lack of moral certainty is unacceptable. Secular intellectual currents, such as naturalism, cannot support the kind of moral absolutism they demand. Religion, especially traditional-minded and authority-emphasizing religions such as conservative Catholicism and Islam, provides an acceptable alternative.
In that case, it might not be appropriate to respond to such a position as if it were yet another apologetic strategy trying to show that God is plausible. The issue is not what is true, but what is acceptable to believe. That is a different matter. And as far as I can see, a degree of relativism does hold when we are questioning ways of life and what is morally acceptable. Moral absolutists inescapably hold false beliefs, especially about the nature of morality. But it is much less clear whether they are not rational in doing so.