What a bunch of baloney. This article is clearly an attempt to portray harems as simple matrimonial spaces. Yet another attempt to exonerate Muslims and their proclivities.
Harems existed for wives as well as concubines and slaves kept for nothing more than pure sexual pleasure. They exist to this day. I have personally seen a few in Saudi Arabia and they are extremely common amongst the rich middle eastern and especially oil rich sheikdoms of the gulf.
They are staffed by a combination of paid call girls and women kidnapped into the slave trade. White, particularly blonde, blue-eyed women are still to this day prized above all others for their rarity, but all races can be found, depending on the tastes of the Harem owner.
Not only this, but the Chinese also have a long history of keeping harems filled with women and staffed by eunuchs.