Relativism is “the doctrine that no ideas or beliefs are universally true but that all are, instead, 'relative' - that is, their validity depends on the circumstances in which they are applied” according to a Dictionary.com entry.
I think all people are moral relativists. Dr. Hector Avalos wrote in Yahweh Is a Moral Monster, a chapter in the book I am currently reading called The Christian Delusion, that “human beings are always the ultimate judges of morality even if we believe in God. After all, the very judgment that God is good is a human judgment. The judgment that what God commands is good is also a human judgment. So Christians are not doing anything different except mystifying and complicating morality. Christians are simply projecting what they call “good” onto a supernatural being. They offer us no evidence that their notion of good comes from outside of themselves. And that is where the danger lies. Basing a moral system on unverifiable supernatural beings only creates more violence and endangers our species.”
The idea of a supernatural being passing morality to humans complicates the world. When different groups claim their god is the one and only true god, without being able to provide evidence, disputes break out resulting in conflicts and wars. History confirms this over and over.
Continuing with Dr. Avalos, “...atheism offers a much better way to construct moral rules. We can construct them on the basis of verifiable common interests, known causes, and known consequences.” By eliminating the religious avenue all together, morality is simplified and can be agreed upon by rational thinking human beings. The God-concept complicates things. I'm not saying that religion hasn't served humanity in some sense. I think it has, but I also think humans need to move into a higher understanding of how life works for survival's sake. In this modern age of nuclear weaponry, wars carry with them the possibility of annihilation. Religion may have provided us with emotional and psychological support over thousands of years, but perhaps it has also taken us closer to Earth history's end.
Relinquishing our beliefs in unverifiable premises (god/s) and analyzing our human situation rationally seems to me to be a better common solution to the warring problems we humans have created through our many religious differences.