I've not seen the film yet (if ever) so I have no opinions here at all.
In general, reading books and watching film, I have no issue with singular characters; black women rap, some have songs such as WAP, other support Trump in earnest, some are matriarchs that usher in social change for the better, others can end up as welfare queens with crack babies, real life has a rich spectrum.
The review above has some strong opinions about PTA's character mix and representations and I'd really have to watch the film through to form an opinion as to whether this is odd for no reason, sloppy, an unconscious tell of the directors world view or a deliberate bit of skewing that forms part of whatever message he wishes to convey.
Like many, I try not to get too deep into a rabbit hole of second guessing books and films, first impressions are often the ones that count most.