Slave Market

I believe the answer to this question is the separation of familes. The following quote can be found in Chapter Two. If this question pertains to a specific chapter, please advise.

Why are parents to lose their children, brothers their sisters, or husbands their wives? Surely this is a new refinement in cruelty, which, while it has no advantage to atone for it, thus aggravates distress, and adds fresh horrors even to the wretchedness of slavery.