as someone that lived in a multi-generational intentional community that had a mennonite/nu-monasticism bent, we got asked the same question. We were also in chicago. Some people of color came to the meeting house (church) but actually in household or the common purse? none that were black and most people of color (latino, asian) were of a higher socio-economic status (went to college, grad school). We went to conferences and gatherings of other intentional communities and the same question was asked. where's the diversity?
I think people of lower socio-economic class have little exposure to things that take time and money to be involved in. who has time or space to garden when you are in a rental, take the bus to work, work for very little pay, and don't even have time to cook food let alone grow it. black people indeed cook of course, but growing it is even more involved. i don't know if it's been historically/culturally respected to go from working in an owner's field to working in...some other white guy's field. that's a big difference between latinos and african americans. many latinos work on farms and have ideas of going back to latin america to grow there own food despite their lower socio economic class.
i feel like black people are trying to live a life that the dominant culture can respect. and how they approach idealism or hope is through their current realities, non-opportunties, whatever their struggles are, etc. if you want to have respect, i think a lot of people look to the people around them to give them that through the other people's values. it takes a LOT of independence and idealism to wander into permaculture and find your own kind of value and then wonder if anyone else shares that, and i feel the communal aspect of the black community doesn't easily allow for such wild independence. i would guess that a black permie would come from a higher s/e class and probably has an education. (just like most other permies).
not saying someone couldn't break the mold, just unlikely.