I think most people outside of Milwaukee or Wisconsin don't understand just how segregated the city actually is. It's "bad", because it does have sort of a pressure cooker effect, concentrating the problems, and it probably hurts and drags down working people and families just trying to get by. There isn't enough of a "mixed" or even a segregated, but black/upper middle-class area those lifting themselves up and out can go to here. It's "good", because the segregation means that the rest of the area is so livable. The hispanic near south side of Milwaukee is a bit dodgey, elevated property crime etc. but for the most part, it's not hard to live quietly and mind your own business and not have trouble come looking for you there.
The box is the few blocks around the intersection where all the riots and fires took place, and the police shooting happened as well.
Empty white space is rivers, freeways, parkland, schools, commercial/industrial property etc. where people don't "live" or have a residence.