Democrats need the criminal vote... that’s a substantial part of their base.
Dems realize the birthrate of the American underclass has slowed considerably - specifically after the 1996 welfare reform. Many hoodrats still breed out of wedlock, but many just pop out one Golden Ticket Welfare Bastard - it is enough to get them gubmint housing, WIC/food stamps, and a free college education. The imported foreign underclass takes up some of the slack, but some foreigners also vote “capitalist” - they are here for the American Dream of yesterday, not the communist utopia envisioned by Dems (taxes are too high).