I'm not talking about objective good or objective bad- I'm talking about morality as a set of rules a given society follows. Each society has its own set of morals. These morals change from time to time and from society to society. The concept of absolute right and wrong is an interesting intellectual exercise, but it's mostly irrelevant.
If absolute morals are irrelevant, then so is the act of murder as to the question of whether it is right or wrong. If cultures dictate morality, then Hitler was right, and so was the antebellum South. Who are you to say your culture is superior - can't be under your logic. One system can only be superior if it more truly adheres to an objective moral standard (which must come from God).