In another hundred years, who is going to point to us for our ignorance and arrogance for something now invisible to us, while lauding another aspect of our lives entirely?

Very true - though I doubt we'll have to wait that long. For starters, I imagine we'll be excoriated for our profligacy with the earth's resources; but there at least we know we're doing it wrong. Fanny knew that leading people from Hinduism to Christianity was what God wanted. I wonder which of the things we now consider virtuous will be as dubious to our successors?