DeviantArt disassociated themselves because they don't want to have legal troubles by having the Inktober trademark on their website.

I think that J.P plagiarized Alfphonso Dunn's book. The content of the books might be the same, as drawing techniques are very specific but the structure and the layout and the way that Parker arranged his book look as a copy paste from Dunn's book.

P.S Check your mail please..