It's a pretty fucking stupid culture war, too. From what I've heard, the movie is very anti-slavery (Viola Davis's character was formerly enslaved herself, I believe), and the movie addresses slavery all throughout.
I wish people had watched the damn movie beforehand before complaining. Yes, there are historical inaccuracies in The Woman King, but what Hollywood historical epic (Gladiator, Braveheart, Lincoln, etc.) doesn't have them? This movie is no different - it's a piece of entertainment, not a documentary.
I, for one, am looking forward to watching this film with the full knowledge that this is "historical fiction" and hopefully will have a good time watching it.