This is "social darwinism". My theory is that this is a variation on "blame the victim". They can't handle the idea that poverty is something that might happen to them, or someone they care about, so they convince themselves that people are poor due to their own mistakes. Single mother? Well, she must have been promiscuous, or failed to use birth control. It never occurs to them that she might have been raped, or widowed, or abandoned, or abused. Homeless? Well, they will say he's lazy, or a drug addict. Tell them that someone lost everything due to catastrophic illness, they simply won't believe you.