That may well be true, but the real question is whether anything else is capable of explaining them either.
Of course it doesn’t. It isn’t even self-consistent. Is it even an explanation? And if it’s coherent, which I don’t think it is, should we therefore suppose that it’s true?
If it can’t, why are all those people disagreeing with him, supposedly on the basis of the bible?
Of course. But the ability of abolitionists and slaveholders both to base their positions on the bible but come to alternate conclusions suggests to me that they were just finding what they wanted to find. I think the abolitionist movement derived not primarily from theology but from ordinary human sympathy and empathy. One may cite Darwin’s revulsion for slavery after having observed it on his voyage.