@Olivier5,
Within a single cultural context, the question of moral relativism and moral absolutism is all the same.
My beliefs about right and wrong are surely almost exactly the same as Joe's. The fact that one of us is a moral relativist and the other a moral absolutist is irrelevant since both of us are part of the same culture and were inculcated with the same values. Within a single frame of reference, relativism and absolutism are the same.
The difference is how we handle being confronted with a culture that is very different than ours. How do we deal with the fact that other cultures have very different ideas about right and wrong than we do.
My moral beliefs about freedom, and equality and human rights are very strong (which is normal for a progressive American). However, I need to recognize that there are people in other cultures (both past an present) that have vastly different ideas. And, in the name of intellectual honesty, I need to accept that there is nothing to distinguish between one set of intrinsic values and another except for sincere belief.
These things are true because we believe they are true.
This is why, when I am confronted with other belief system, I feel it is important to understand that other people have the same sincerity in their beliefs that I do.
My culture is the dominant culture. We have military power, economic power and cultural power to pressure other cultures to submit to our values. That doesn't make us right.