medievalpoc Answer:
Since this ask is specifically about anti-Black racism and its association with chattel slavery, my “thoughts on it” are pretty irrelevant. But what I can do is basically show you where to look for diverse voices and educated writings on this matter:
Discussion here: http://medievalpoc.tumblr.com/post/81808959018
Discussion here: http://medievalpoc.tumblr.com/post/81390891942
Syllabus with Reading List: http://faculty.smcm.edu/ljhall/pamethn.html
On The Enlightenment as the template for Modern anti-Black (and other) Racism (quotes from Kant; Hume; Goethe): http://medievalpoc.tumblr.com/post/132938218093
More here: http://medievalpoc.tumblr.com/search/enlightenment
On Conflicting Sources: http://medievalpoc.tumblr.com/post/77699653807
On Inaccessible and/or problematic Sources: http://medievalpoc.tumblr.com/post/81781216735
The Invention of Racism in Classical Antiquity by Benjamin Isaac (sample at link)
Barbarian Invasions and the Racialization of Art History. Eric Michaud. OCTOBER 139, Winter; 2012, pp. 59–76. Massachusetts Institute of Technology.
‘Race’, ‘Nation’, ‘People’: Ethnic Identity Construction in 1 Peter 2.9 David G. Horrell. New Testament Studies / Volume 58 / Issue 01 / January 2012, pp 123 143.
Answering the Multicultural Imperative: A Course on Race and Ethnicity in Antiquity Author(s): Denise Eileen McCoskey. Source: The Classical World, Vol. 92, No. 6 (Jul. - Aug., 1999), pp. 553-561. Published by: The Johns Hopkins University Press