I think such abstract conceptions of morality should either be based on or connect to an anthropological theory of how and why morality changes. To simply claim "slavery and exism" were morally "simple" dilemmas to solve strikes me as ahistorical.

I know the origin of ziggurat, I just meant the curious use of "tell" to refer to such hills, and its purported Arabic origin. After checking Wikipedia it actually seems to have made it to English directly from Arabic.

That makes a lot of sense. I'm assuming that the word went from Arabic to Spanish, then to the new world where it was applied to ziggurat-hills?

What do you mean by "tells"? Coincidentally "tel" is the Arabic word for "hill".