The slaves don't eat solid food, maybe a cheat bug?
Maybe it's because i used cheats to get to the black market but after getting the solid food upgrade (and i made sure each slave had complete access to the solid food) they still complain/ are horrified about eating liquid food and being dependent on it. I'm not trying to step on anyone's fetish, but It would be nice if i had the option for solid food earlier on, solid food doesn't seem like something illegal on the black market, just a suggestion. Also once it described a female slave who believed slavery was wrong as "a liberated men have no place in free cities".
I'm on Free Cities 0.10.7.1 mod version: 4.0.0-alpha.27, build: 1207, commit: 61298b58