For what it's worth, so did the black producer of Django, Reg Hudlin, but regardless, here's the quote:

“When you look at Roots, nothing about it rings true in the storytelling, and none of the performances ring true for me either,” says Tarantino. “I didn’t see it when it first came on, but when I did I couldn’t get over how oversimplified they made everything about that time. It didn’t move me because it claimed to be something it wasn’t.”

http://www.thedailybeast.com/newsweek/2012/12/09/quentin-tarantino-on-django-unchained-and-the-problem-with-roots.html