Nope, I haven't read it - I just skimmed it a bit after my last post.

I don't really see the logical relationship between the quote you give from the book (an argument about the benefits of keeping those scary black people locked up) and the historian's note, beyond the fact that one is an argument in favor of slavery, and one is an argument against.

I don't think a detailed judgement of that book is the best use of either of us's time, I'm just giving the reasons for my position (slavery probably isn't just a question of false beliefs), I don't expect much utility from having a clear picture of American slavery (cf value of information and all that).