Yet (even) the BBC says:
The Roots of Slavery The term slave has its origins in the word slav. The slavs, who inhabited a large part of Eastern Europe, were taken as slaves by the Muslims of Spain during the ninth century AD.
the main religious texts of Judaism, Islam and Christianity all recognise slaves as a separate class of people in society. Going back further in time the Mayans and Aztecs kept slaves in the Americas, as did the Sumerians and Babylonians in the Near East. The Egyptians employed huge numbers of slaves, including the Jews, Europeans and Ethiopians.
The Greeks and Romans kept slaves as soldiers, servants, labourers and even civil servants. The Romans captured slaves from what is now Britain, France and Germany. Slave armies were kept by the Ottomans and Egyptians.
In Imperial Russia in the first half of the 19th century one third of the population were serfs, who like slaves in the Americas, had the status of chattels and could be bought and sold. They were finally freed in 1861 by Emperor Alexander II. Four years later slavery was abolished in the southern states of America following southern defeat in the American Civil War.
In Africa there were a number of societies and kingdoms which kept slaves, before there was any regular commercial contact with Europeans, including the Asanti, the Kings of Bonny and Dahomey. http://www.bbc.co.uk/worldservice/africa/features/storyofafrica/9chapter1.shtml
the concept of slavery pre-dates the Slavs. You read it in Assyrian and even earlier Sumerian texts. Slavery came about with the transition to agriculture and animal husbandry.
however, within the American context slavery came to mean in the 1800s exclusively Africans. Sure, there were Irish indentured servants and workers like Chinese indentured laborers. Yet for blacks remember that this stigma remained even after the civil war - right down to the Democrat Woodrow Wilson’s endorsement of ‘Birth of a Nation’ and the desegregation in the 60s.
Sure it’s been hijacked by the Democrats (don’t they always hijack divisive issues?) but that doesn’t mean to dismiss it by whatabouttery.
The ideal historical teaching should be
Slavery has been part of most agricultural societies since agriculture and animal husbandry arose. In the 1700s in north America it became exclusively African American slaves (that is before the USA was even created).
It has been generations since slavery ended, since Jim Crow laws ended, since the civil rights movement. There are inequalities, but the correct way forward is not to keep segregating people by race - in census, in terms etc. but to give the poor opportunities not hand-outs.