I’ll be honest, I don’t really subscribe to that reasoning. A lot of things like this are called “divisive,” and what is meant by that term is simply that it upsets white people. That’s what makes it “divisive.” For decades, there were racist depictions of American Americans, all sorts of tropes, stereotypes, and jokes, but it wasn’t viewed by whites as divisive because most didn’t care what African Americans thought, and had a societal position of power anyhow in which African Americans didn’t have a sufficient voice to make the complaint heard.
I actually think it’s a little bit ironic to say, “Keeping white people happy so they don't hurt blacks doesn't help in today's climate,” with the proposed solution being that black filmmakers should not make this film, in order to keep whites happy.
If people aren’t interested in this topic or film, they won’t go see the movie, which seems to be the case anyhow.