The movie and the book are a lot closer together than you would think btw. Might want to give it a re-read, esp with what you know now about the common (far)-right arguments. Not that the arguments in the book are good mind you, it mostly falls back on 'this is a science trust us' which is quite weak.

The movie also does have black people in it, in fact the strategic savior of the human race was a black woman. Source (the rest of the propaganda clips also has quite a lot of poc in it, even if the principle cast included none.

And that brings me back to the racism in the book, while it doesn't have overt 'I need to shout slurs at nonwhite people' racism, it contains quite a lot of 'other species/animals/countries (it nicely never uses the terms in a racist way, but it speaks about these groups in similar matters, so it is quite obvious that this just leads to racist bs as we have seen a lot in our times) as in conflict and the one breeding faster (!!!) wins the conflict. It seemed clear to me on which side of the debate about for example native americans vs europeans the book would be (I'm from city X and I say ...).

Other fun fact about the book vs movie. You prob know the 'violence solves more problems bla bla bla' 'what would the cityfathers of hiroshima say' lines from the movie, these are also in the book, but there the argument (due to in part being about animals) is worse.

So long story short, I'm happy for Samuel R Delany that there was some liberation for him which is good (also note that the realization about the non-white people should have come a little bit earlier as the girl is called Carmencita Ibanez (I'm very western European btw, so I might be wrong here as I'm not that great about all the subtleties of various racial interplays in the Americas), also she was apparently a bit of a hussy according to Juan "Johnnie" Rico) esp as it was a different time, and science fiction from that era can be dire (before that it gets even worse!) compared to our current morals, but the book itself is still very problematic (it gets weirder if you interpret the book as being told by an unreliable, slightly dumb nepobaby, which imho the book supports).