Idk why do dogs eat all sorts of random shit (figurative and literal) when they have food inside the house? They're not evolved according to our sensibilities so they just sort of do what they do.
I also suspect modern, especially urban minorities probably eat a 100% garbage trash diet of hyper processed corporate slop foods so it's possible that instead of getting the regular spectrum of nutrients that people who eat human food do they have various deficiencies that cause them to eat crap like soap and corn starch instead of just, like, a carrot or something.
Unfortunately unlike canines everyone has to pretend that said urban minorities are capable of functioning equally in our modern industrialized world and thus like 50% of the problems in the US. Could you imagine if there were no black people in America? How much simpler and less irritating things would be?
I'm not saying black people should all disappear, I'm just saying from a purely functional perspective it's incredible how many fewer problems we'd have if they did.