Also, exploitation only applies if the workers 1) have no better option and 2) their options are artificially constrained by the party offering their only option. Anything else is simply failing to understand their situation.
Is theRe a historic reason for this, or example of schellings segregation model?
Simply because they are abiding by minimum wage laws and making less than you are per hour does not mean they are exploited. Simply because Detroit is segregated in practice (as a result of factors beyond the control of most of the individuals) does not mean these workers are exploited. The fact that the dinosaurs went extinct even though they too, like us, deserve a chance to exist does not mean these workers were exploited.