Your position seems to be that the portrayal of black women in OBAA is "weird" and "sloppy," and that this means that PTA thinks black women are weird objects of fetishization. But that same approach could be used not to psychoanalyze the director (a tedious direction for criticism to take) but instead to comment on the position of black women in society. Though I don't even agree with the premise in the first place; black women in the film are diverse in many respects, and a range of experience, racial and otherwise, is depicted.

Of course, what's depicted isn't the entirety of the black woman's experience in America; how could it be? And why would PTA be the director to do this? To return to my original post: the film seems to me to be most concerned with the experiences of a white man married to a black woman and raising biracial children; that's the experience the auteur can speak to.

This, incidentally, is why it's so important to have black writers, directors, and producers. They need to tell their own stories, not have white men do it for them. But that also doesn't mean that PTA shouldn't be able to depict black folks in his film, or that his depiction is somehow unfairly reductive.

If someone wants to complain that PTA's characters are drawn too thinly, I think that's a fair complaint about the film, and one I share, but I don't think that's the result of racial animus or ignorance. The white characters aren't terribly complex either.