I feel that as Christians we tend to take a morally relativistic approach to explain past cultures in the Bible by saying, "That was just the culture at the time". Yet moral relativism, I would hope, is not a plausible ethical theory for any Christian. For examples, Lot offering his daughters to the men of Sodom did not appear detestable in Genesis, and the many other situations that seem odd/wrong to us nowadays but “okay” in Bible times. So are we as Christians being inconsistent with our beliefs? -- Tim Sumerlin
Moral relativism is not the same as cultural relativism. Cultures contain moral and non-moral elements. Lot offering his daughters was a moral matter (a wrong). Honoring one's guests is a biblical principle, but also a cultural feature of ancient society, which led Lot to value his angelic guests over his own daughters. We see a similar dynamic in Judges 19 and in Genesis 19.
Of course the two are related, but the more open-minded approach (the possibility of some parts of scripture being culturally conditioned) need not lead us down the slippery slope of relativism or postmodernism.