How about this? There actually was an African-American SF writer in the 1950's named Benny Russell. Elements of his life were shown to Ben Sisko by the prophets but the details were changed to suit their purposes. After all, it's been established that they can make you see whatever they want you to see.
Not out of the question, I suppose, but just by Occam's Razor, the simpler explanation is that the whole thing was symbolic.
Frankly I feel the whole episode was flawed on a conceptual level. I mean, sure, it was a great way to tell a story about '50s racism, and in that respect it was very powerful. It would've made a fantastic episode of an anthology show. But as a piece of the DS9 narrative and the ST universe, it isn't very well justified. It's the kind of story that Avery Brooks and the show's producers would want to tell in order to comment on racism, and as such it was superbly done, but it's not really that plausible as a vision the Prophets would give Ben Sisko. I mean, it's so indirect and overelaborate, even for them. It doesn't really fit their other visions and visitations. Rather, the writers adjusted the idea of Prophet visions to fit this story, because it was a cool story. It was about sending Ben Sisko on a trip through the Twilight Zone. (Fittingly, given that the story was by Marc Scott Zicree, author of The Twilight Zone Companion
.) But it was always an awkward fit into the DS9 narrative.