Racist Apologist Bullshit, or simply complete ignorance, which is more insidious...

. When you've finished the Foner book, read Ira Berlin's "Many Thousands Gone: The First Two Centuries of Slavery in North America" Harvard University Press 1998. Then have a look at Chapter 5 of James W. Loewen's "Lies My Teacher Told Me" Simon & Schuster 1995. Then you might have a few facts on hand.