The Hollywood Movie That Destroyed Black Americans Forever - Thomas Sowell

The fact that Haley's novel was sold on the non-fiction self is more important that the plagiary. Genealogy prior to the civil war has been debunked.
https://en.wikipedia.org/wiki/Roots:_The_Saga_of_an_American_Family#Historical_accuracy

Kunta Kinte from Gambia is completely fabricated. Mark Ottaway went to Gambia to investigate.

http://www.friendsofpaxos.org/Mark-Ottaway-1939-2016

Mark Ottaway, celebrated Times journalist, great lover of Greece, long time Paxos resident and dear friend to many of us died in England on 22 December 2016, aged 77.

In 1977 he travelled to Gambia during the touristic frenzy that had resulted from Alex Haley’s bestseller, Roots, which purported to trace the history of the author’s Gambian ancestors. Book in hand, Ottaway began to notice discrepancies. The geography was not as described. His sources were neither authoritative nor reliable. “Tangled Roots”, which was published across two pages in The Sunday Times in 1977, was a piece of work that earned almost as much abuse as admiration, but it stands as a model of investigative journalism.