Maybe you didn't hear. Minority unemployment is at a historic low.
The problem with your logic is Amazon raised their MW to 15 and still needs employees.
At $15 minimum wage, there are plenty of people that will lose eligibility for programs such as Medicaid, Foodstamps, Welfare, etc. However, at least in states like NY, that money will still be spent by making people who are not citizens or permanent residents of the US eligible for government-funded health coverage which mirrors Medicaid (for example, people with a student visa can get NY Essential Plan at $0 premiums and $0 co-pays if they qualify based on income (which supposedly they would, as they aren't allowed to work in the US).