Good thing he didn't see
Firefly can you imagine the howling he would put up since the Black heroine is married to a

White man.
No doubt there would be some way to trivialize Gina Torres' role. Anything to diminish a black actor's role in the name of fighting racism is an ironic way to advance a cause. Too many people find a way to "prove a point" at the expense of the very thing they are trying to accomplish.
Oh, did anyone notice a distinct lack of Avery Brooks in that whinging? A black space captain who was not marginalized, not killed off, and pretty damned important. And was the lead of the cast to what many consider among the best Star Trek has to offer.
How about Don Cheadle in Mission to Mars? He's the lone survivor of a slaughter of his crew and despite going slightly insane (he was alone for I believe a year and some months so anyone probably would be slightly unhinged) he still was able to pull back and prove to be a valuable contribution to that story instead of killed off 10 minutes later. BTW, all his fellow astronauts who died were white.
What other sci fi characters can I come up with who are black but fail to fulfill an expectation of being marginalized and killed off fast?
Michael Dorn (Worf) from TNG. Technically he was a black man playing an alien race, but he's still a black man and other than a big-ass grill on his forehead, his skin color was not hidden. I'm sure there's an argument lurking that he was from a barbaric or primitive race but that should be b.s. to anyone who ever watched Star Trek or TNG on a regular basis.
Christopher Judge (not Plummer

) (Teal'C) of Star Gate SG-1. Again, an alien but hardly a sterotype nor relegated to marginalized status.
Teyla from SGA, a human from an alien world. Her people were primitive, but then so were virtually
all the people there, regardless of race. She proved to be more than a phone operator.
Babylon 5 had Doctor Franklin. A doctor,
and a black man. Imagine that. He was given his own storylines and was not some trivial character either.
Ford Prefect (Mos Def) from Hitchikers Guide to the Galaxy. He was also an alien but other than Arthur and Trillian, so was everyone else.
Will Smith in I, Robot. He starred as the main character of the movie. He did Independance Day too. And the Men In Black movies. But I hear he's the "Token N**** In Charge" as it's so succinctly called by certain black activists (even though I'm sure some of the other black actors would disagree woth both the phrase and the callous dismissal of themselves). I don't know if Dave Chapellle coined the phrase but he sure as hell popularized it.
Or maybe that's Samuel L. Jackson. He was a major supporting character in the Star Wars prequels.
The Matrix movies had numerous black actors in major roles.
Would Hermes from Futurama count? It's a cartoon I realize, but still science fiction-y.
Or Fro-zone from The Incredibles?
I'm sure I can go on but I'm getting a little long in the post here.
It is easy to cherry pick an actor or character to make a point and "prove it" even as you ignore other roles and actors who disprove it. But try to argue otherwise, you're either accused of missing the point, ignorant of the "proof," finding exceptions to the rule (despite an ever growing number of "exceptions") or in extreme cases considered a racist as a fast way to write off your objections to the claim.
And yes, this is a far cry from saying there is no more room or need for improvement. It
is however a call out that you can't keep using the same lines of trivial roles or that there's nothing there for more than a small number of black actors. It's growing. It's not as broad as it should be but it's also unfair to keep denigrating other actors just to push forward a cause that doesn't need that kind of inconsistent and false remarking.
Personally if I were one of the actors I mentioned above and told I was being relegated to glorified telephone operator despite my accomplishments for the sake of a poorly thought out defensive whine, I'd be offended at the writer.