Prisoners are paid for this work. Because they do not pay for their expenses the rate of pay is limited.
Nevertheless, this is a legltimate and helpful source of income for people who have few options for earning money legitimately.
Typical of leftist stupidity, the Mayor lost a chance to help some of the most unfortunate among us because of his commitment to being politically correct which equates to being morally reprehensible.
Bravo!
At least they were American prisoners. If Mike had his way it might have been done for a few cents cheaper using Chinese prisoners.