This is an outstanding film about a story I knew nothing about. However, my review is more a review of IMDb and its voting system.
I note that this film has, at the time of writing twenty-two 1 star reviews. Maybe these are genuine but I suspect they are not. For one thing the film has not had many screenings so have as many as twenty-two different people really hated it that much?
Secondly, 1 star films do not get selected for the Toronto Film Festival or for the opening night film for the London Film Festival. The programmers and selectors of these highly regarded festivals are at the top of their game and each year they are offered several thousand films. None of them are going to risk their hard fought reputations on selecting a bad 1-star film.
My feeling is that these 22 people are members of the KKK who hate black people or else they are people who are jealous of the those involved in the production.
Either way IMDb needs to have an algorithm that can deduce whether these people are genuine, or not. Maybe they are and the press reviews so far, which rave about the film, are wrong, but maybe these people are racist bitter bigots who hate the success of others because they themselves are failures and they have nothing better to do in their small sad lives but set up false IMDb accounts and vent their spleen in the only way they can.
Time as they say will tell.