You see that kind of extreme historical utilitarianism all over the place in revisionist historical scholarship, though. "Sure, Chinggis Khan's conquests killed more human beings than World War I, and so thoroughly ruined Iran, the Middle East generally, and the ancient trading cities of central Asia that their populations may not have recovered to pre-mongol levels until the 20th century, but without the streamlined commerce and travel between China and the west his empire ushered in, all sorts of rich cultural, economic, and technological exchanges would never have happened."
The *really* dark and twisted moral argument about the West African slave trade is that there's a non-trivial historical case to be made that the slaves trafficked to North and South America (as always, the Caribbean slave experience was frequently its own special kind of hell that no human soul should have had to suffer), particularly the U.S. and Brazil, wound up emancipated *before* many of their compatriots back in Africa. E.g., the Toucoleur Empire, a large Senegambian state led by a charismatic Islamic reformer named Omar Saidou Tall, just about extinguished several large remaining pagan tribes, kingdoms, and settlements in West Africa below the Sahel during the 1870s, 1880s, and 1890s, taking slaves all the way. Now, I'm not a West Africa expert - just an interested outsider - but the story is a lot more complex, human, and fascinating than American discourse gives it any credit for. The stories of the Mali, Songhai (which lasted to 1901!), and the other great West African empires are amazing, but just as full of cruelty as anywhere else on the planet (slave societies, all), and because less technologized, more dependent upon pliant human labor to perform large-scale projects. The easiest way to get pliant human labor in large quantities is, of course, slaving.
You see that kind of extreme historical utilitarianism all over the place in revisionist historical scholarship, though. "Sure, Chinggis Khan's conquests killed more human beings than World War I, and so thoroughly ruined Iran, the Middle East generally, and the ancient trading cities of central Asia that their populations may not have recovered to pre-mongol levels until the 20th century, but without the streamlined commerce and travel between China and the west his empire ushered in, all sorts of rich cultural, economic, and technological exchanges would never have happened."
The *really* dark and twisted moral argument about the West African slave trade is that there's a non-trivial historical case to be made that the slaves trafficked to North and South America (as always, the Caribbean slave experience was frequently its own special kind of hell that no human soul should have had to suffer), particularly the U.S. and Brazil, wound up emancipated *before* many of their compatriots back in Africa. E.g., the Toucoleur Empire, a large Senegambian state led by a charismatic Islamic reformer named Omar Saidou Tall, just about extinguished several large remaining pagan tribes, kingdoms, and settlements in West Africa below the Sahel during the 1870s, 1880s, and 1890s, taking slaves all the way. Now, I'm not a West Africa expert - just an interested outsider - but the story is a lot more complex, human, and fascinating than American discourse gives it any credit for. The stories of the Mali, Songhai (which lasted to 1901!), and the other great West African empires are amazing, but just as full of cruelty as anywhere else on the planet (slave societies, all), and because less technologized, more dependent upon pliant human labor to perform large-scale projects. The easiest way to get pliant human labor in large quantities is, of course, slaving.