Moral absolutism and relativity, the argument
In ancient times, the pantheons of gods allowed members of a populace the ability to chose lifestyle modes that suited them. If you chose not to follow the dictates of Zeus, for instance, you could always move to paying homage to Poseidon. It was merely a matter of moving from one temple to another.
The rise of Christianity in the west changed all that. No longer was there a choice between what lifestyle or ideology one could follow. Suddenly, there was but one value-laden system, and you had to follow it or die.
By the eighteenth and nineteenth centuries, when the protestant church had successfully broke off from it's catholic forebear and lead the way for the rise of deism and atheism, alternative schools of thought on many subjects began to proliferate. Thus began the battles over values and ideals.
The Christians have long proclaimed that there are no such things as morals without a god to proclaim and enforce them. Moral absolutist in the west, regardless of religious leaning, tend to assume that there must be a centralised morality. Unfortunately, they tend to assume that the Christian view of morality should be that central morality. Even atheists who are born in Christian countries uphold the Christian ideal.
If you proclaim a centralised morality, then you have to figure on what basis you set your moral standard. Since morals are derivative of tradition, then in countries where the traditions come from Christianity, your moral standards would invariably come from Christianity.
Yet, in countries where the uphold Buddhist traditions, the moral standard would come from Buddhism. This is at odds with moral absolutism, since the Buddhist do not look at the world in the same way that the Christian does.
The only justifiable outlook, then, is moral relativity. I, for instance, am perfectly capable of judging what is right or wrong for myself. It may be that what is right for me is detrimental to you, but that does not make it absolutely wrong. To proclaim that something is absolutely wrong just because it is wrong for you therefore creates and injustice against me.
Until the world is free of irrational precepts and religious traditions, and people are able to think without reliance on political, social, or religious dogmas, the idea of a centralised morality that is absolute is impossible. Should such ever become a reality, then moral absolutes would become irrelevant.
I am become death, destroyer of worlds