I guess i shouldn't have been so shocked given humanity's track record of inhumanity to others.
Visiting these sites is interesting from a historical perspective but it is mind numbing from a human perspective. Expect to be appalled.
The builders and occupants of these forts went to very great lengths to taunt and crush the spirits of the slaves: The hell of the dungeons, packed full with slaves, no light or air, an unbelievable stench, a floor thick with faeces, vomit and blood, while directly above the heavenly chapel and the commander's godly quarters.Very biblical connotations.
You might think that conversion to christianity might have been the objective here but no: Heaven and god were literally and figuratively out of reach for these broken souls.
The uncomfortable question arises: If slaves were valuable why treat them so badly? Surely as a slave trader its not good for business if your slaves die in such numbers before you can sell them? Distressingly, the supply of slaves from the surrounding fractious populace was inexhaustible: Africans profiting from the miseries of their own people.
And why build a fort at all and garrison it? Certainly not for fear of the population, but rather to protect themselves from each other. If there is no honour amongst thieves, think what that says about slave traders. The occupants of each castle eyeing the other suspiciously across the bay, on the lookout for any sign of weakness, opportunity or threat.
Be sure to engage a knowledgeable guide to understand the centuries of tragedies that endured here. If the walls could talk... Thankfully though, I am not clairvoyant, it would have sent me mad.