By the 1870s 95% of the prison population of the south was black. Laws were enacted targeting freed slaves in order to incarcerate them and put them back on the plantations they'd been freed from. Now, I play fast and loose with history in this game, but please understand that every decision I made is with purpose. The plantation owner is a racist who, while he might enslave a white person, would not choose to kill one and turn him into a zombie. He even disagreed with creating a living zombie of a white woman (in his own misogynistic and racist way). He only attempts to kill the protagonist (a white man) bc you the player have decided to fight him, but that wouldn't have been his choice. He's trying to make the protagonist his right-hand man. Now, I didn't mean to suggest that no other races were subject to convict leasing, but the entire first half of the game explains why the protagonist has found himself in this predicament and should, with some thought, explain why many freed slaves would have no way of getting themselves out of it. Neither he nor his family could pay his way to freedom. In fact, the game is set in Florida, which outlawed convicted leasing after the death of a white prisoner who should have been freed instead. His family sent the money to the prison to secure his release, but it was likely stolen. I think it's telling that it took the death of a white man to end convict leasing. Many, many black people died in the harsh conditions they were thrust into, particularly in Florida, which was said to have had the harshest conditions of any state.
I agree with the rest of your assessment; however, I'm not sure exactly what to do to fix the issues. I've thought about adding an interactive flashback during the long cellar speech, but I'm not sure what that would entail and then the player would be playing as the antagonist, a truly loathsome character. I could try to shorten the speech, but that would only be to condense things. I don't think there's any information I could remove that isn't necessary to the player to understand exactly what's happening. It's certainly wordy, tho, so I'm sure some of it could be condensed without losing anything. As for the graphics... unless I hired someone to make them, they're kinda the best I can do.