Personally I don't think they care about black fans. Sure, they'll gladly take our money and it's beneficial to see black fans sprinkled among white ones to tout diversity. But is that diversity really for blacks, or just to make whites feel better about themselves? When I look at Finn particularly that is a black character that doesn't do much in terms of presenting a positive image for black kids. He has some good traits but they are overshadowed by the bad ones. And the other black characters have often been in the background, like wallpaper. They get diversity points but that's it. And I think that's the view whites have of blacks. It's finally okay for you to be seen after centuries, but you aren't supposed to say much. Unless it's to support the important white characters. And if you die you are unmourned and forgotten.
Now, I'm sure some will mention Finn, Lando, Saw, Mace, Korr Sella, the at least three 'black' female Jedi in the prequel films, even the one black Imperial cadet and the one Mandalorian (voiced by Gina Torres I believe) both in Rebels, but I think my statement stands. Look at how Lando has been treated. He is one of the most iconic characters in the original films that they can't even come up with a decent idea of what he's been up to (to be fair, they screwed that up with Luke, Leia, Han, Chewie, 3PO, and R2 as well). Mace is one of the best depicted black characters in Star Wars IMO, so I don't have many gripes there, though I wish we had seen more of him in action in the prequel films and in the Clone Wars cartoon. The black female Jedi were given short shrift, but so were a lot of prequel Jedi. The main problem I have with Saw is that they had him go out like a punk which didn't fit the character they had established as being a hardcore fighter. Let him go out fighting the Empire. He just wouldn't give up. I haven't watched enough Rebels to make a judgment about the black characters on there, but you don't see them on any of the promotional material (the pilot did get a YA book series though), so there you go in terms of how important they are to the overall story. There is also a black Imperial officer in the canon novels, but I haven't read them so I don't know how important she is. From what little I know she is not running things.
In comparison, Star Trek has depicted black characters far better. Just having Uhura on TOS was groundbreaking and then they had a black commodore and a black genius (albeit it he was mentally unstable) in Dr. Richard Daystrom. TNG had Geordi, and though they blueballed him, and had Data and Wesley be smarter than him, he still contributed. DS9 had Captain Sisko. They undercut him a little, but Sisko is the most well developed black character in any sci-fi show or movie I've seen ever. He was a good father, a tough fighter, a smart warrior, and a lover and family man. Sisko was also racially conscious. He didn't always get the screen time, but DS9 was a very well-written show. VOY had Tuvok. I didn't care for them having to make a Vulcan of all people mentally weak at times, but still I thought Tuvok was a worthy successor to Spock. I haven't watched all of VOY but I from what I've read they also gave Tuvok some shows to develop his character as well. Trek took a step back with ENT, and Mayweather was just sort of there. He got a handful of episodes throughout that show's run and even a little white treat in the final season, but he was never well developed. ENT at least had a black man, Emory Erickson, invent the transporter. So two of the key geniuses in Trek lore are black.
The Abrams films beefed up Uhura's role and made her the third most prominently featured character behind Kirk and Spock. Discovery could push the ball even forward with the depiction of blacks and black female characters in particular with Michael Burnham. This is the first series since DS9 to be centered around a black character. And already Burnham, from what I've seen, read, and heard, Burnham is one of the brightest and most capable officers ever in Starfleet.