@igm,
Igm, I agree with your statement that "If [people] have an understanding of what is believed by the majority to be immoral then they at least have that as a reference point. If society shuns morality and just has ad-hoc ethics I believe some may suffer because of it."
But remember my point: a general moral framework is necessary for the well-being of societies (which is undoubtedly why they are found to be cultural universals), but individuals who would live a mature life cannot live as moral automatons. They must generate ethical decisions with both a moral grounding (your point of reference) and an acknowledgement of the dynamic complexity of concrete ethical life.
Morals are general (even abstractly universal) but ethical situtions are concrete and particular. One must choose among the moral rules that might be applicable to a particular situation. And how he edits, or interprets, them to better acknowledge the realities of his ethical problems reflects the quality of his ethical and moral life.
This shows me the value of these threads. Without your reminder of the relevance and value of moral systems I would probably have overstated the importance of ad-hoc (as you call it) situational ethics. Together--in non-competitive debate--I (can I presume the same for you?) have arrived at a more balanced perspective.