the institution of slavery had been in place for centuries prior to any ship ever setting sail into the middle passage. my guess is that anyone who participated in it (whether as a captor or as a seller) gave little thought to what happened after a given transaction.

at the outset of what became the international slave trade, how could african businessmen/warlords have known what was about to happen to their "brothers and sisters"? maybe a century or two later they figured it out. but by then they had little to no power to stop it.

i wouldn't place the entire burden of guilt on the conquering europeans, but the fault clearly lies with those who racialized slavery thereby making it the peculiar institution on which this discussion seems to be built.

bottom line: race did not always define slavery. but when it first did, it was the europeans who rewrote the rules.