The problem with short excerpts like this is that I don't have enough context to know exactly what the mayor intended to mean.
If I want to go in giving him the benefit of the doubt, and I don't see why I wouldn't, there are some contexts that could make sense.
He might be referring to America in general rather than just Chicago. Or, he could be speaking broadly about how exploited people always do most of the work, and just said slaves and indigenous people as examples of exploited people.
