This is a particularly weak set of arguments: Canada and the Southern US have many _other_ core differences that could explain their different outcome, and so d

This is a particularly weak set of arguments: Canada and the Southern US have many _other_ core differences that could explain their different outcome, and so do African Americans and Africans (neither of which are homogeneous by the way, and especially not the latter). On top of that, it doesn't matter for reparations-purposes whether slavery was, overall, efficient. What matters is whether an institution harmed someone and therefore owes them compensation.