Yes there's the racist (wrong) belief that only black people get government benefits, but there's also the additional belief that there's some secret welfare system that only black people have access to.
Remember how welfare reform was supposed to solve all of this? There basically isn't welfare. There's a tiny bit of income support for some single parents, there's a tiny bit of food stamps, there's an even tinier supplement to food stamps in the form of WIC, and then there's Medicaid which has genuine value but doesn't arrive in the form of cash. Ok, a bit of housing subsidy support with long waiting lists. No one is going to live on this largesse completely voluntarily.