Are those two “elephants” the Africans raiding African villages and selling people, and the indentured servitude done by the English to the Scots and Irish (plus other English)?
Not the Scots Irish.
The Islamic (Arab) capturing of tribe members in East Africa for personal use and sale in the WW slave trade on the East African Coast.
They sold to Arabians, Indians and Heathen-Chinee along with East Coast Mediterranean peoples like Syrians, Lebanese and other “muslim conquered” populations.
BTW...Arabs, as a race, are of Caucasian descent.
The first thing you mentioned was indeed one of the two "elephants;" the other elephant was the... umm... "middle eastern" role.
Dad was very aware of Brittania's history of indentured servitude and penal transportation, but I don't remember him bringing it up WRT "Roots."