Some confused thinking here -
Domestic slavery is wrong, perhaps even a crime. Commercial and industrial slavery, however, are not only acceptable, they are to be encouraged. So we have zero hour contracts and workfare.
Where, I wonder, does the trafficking of sex slaves lie in this contradictory situation. It is, after all, a business. Perhaps Mrs. Thatcher's tutor, Sir Keith Joseph, could our guide: "We must teach the young that there is nothing immoral in making a profit". Or Milton Friedman: "a corporation cannot be ethical; its only responsibility is to turn a profit". These gentlemen would surely have approved of slavery in all its forms if it was profitable.