The age of the Earth is not a question of morality. My point is that morality is ALWAYS subjective to where your culture, so how can there be an absolute truth, and if there is one why doesn't everyone know what it is?
My point with the age of the earth example was simply to show that just because different groups have different opinions it doesn't mean that there's no answer that's any better or more consistent than another.
Different groups invariably believe different things, cultural and tribal prejudices and so forth. That doesn't negate the fact that some predisposition and prejudices will be ill-founded or utterly baseless.
Different groups have different moral standards for various reasons, but there are also human universals, like the prohibition of murder and theft.
The fact that there are these universals suggests that there are basic axioms of morality that all people, in all places have some kind of access to, or understanding of. It may therefore be possible to discern what these axioms are, and to expel the unjustified and arbitrary cultural assumptions.
See what I wrote in the 'right, wrong' thread if you want to know more about my opinions on this subject and have the time to read it
But also, if you're saying that morality is
entirely subjective, then you must concede that no moral idea, no matter how utterly whacky and senseless, is any worse or better than any other.
Complete moral relativism is entirely unworkable and necessarily absurd, and runs completely contrary to human intuition.