What part of slavery does Equiano really want people to understand?

Equiano grew up around slavery, and in his culture it was the norm. His father owned many slaves, as did other. What he wanted people to understand was the cruelty involved in abduction, beatings, over crowded slave ships, starvation, rape, and separation from family (his sister was abducted alongside him).

In the end he says, "Hitherto I had thought slavery only dreadful, but the state of a free negro appeared to me now equally so, and in some respects even worse, for they live in constant alarm for their liberty . . .a mockery of freedom." 779