Coleridge recounted in Table Talk 1830-1832:
"Mrs Barbauld told me that the only faults she found with the Ancient Mariner were — that it was improbable and had no moral. As for the probability — to be sure that might admit some question — but I told her that in my judgment the poem had moral, and that too openly obtruded on the reader, It ought to have no more moral than the story of the merchant sitting down to eat dates by the side of a well and throwing the shells aside, and the Genii starting up and saying he must kill the merchant, because a date shell had put out the eye of the Genii's son."
This gains a very significant moral when one realizes that though are many nasty side-effects to European imperialism, one of the most unpleasant for Tahiti certainly was venereal disease. When Captain Cook arrived in Tahiti, he was aware that island sexual mores were very different from British ones and wrote about the previous British expedition to the South Seas in his journals. When the Dolphin left Polynesian waters, so many nails had been taken out of the timbers and traded for sexual favors, the ship almost split apart during a storm. This time the Tahitians got the much worse end of the deal with "the English disease."
Cook did not like to admit that his precautions to make sure the ship's crew were free from VDs were at fault and at first tried blaming the French of the Spanish. 'However,' he wrote in his journals, 'this is little satisfaction to them who must suffer by it in a very great degree and may in time spread itself over all the Islands of the South Seas, to the eternal reproach of those who first brought it among them'.
Coleridge turned the consequences back on the British in The Ancient Mariner. A two hundred man crew all dies (save for the Mariner, who shot the albatross that was later hung around his neck) after a run-in with Death and a lady named 'Life-in-Death.' What gift the lady gave the crew is therefore given is perhaps easy to guess.
In the words of Pangloss, it is a thing unavoidable.