Remember: liberal do-gooders always have an ulterior motive. And that was the hidden motive of LBJ's "Great Society" - to create a welfare system that would trap people, and their children and grandchildren, forever in poverty. That is why the rules were written deliberately to deny welfare to intact families, and to lavish it on single mothers and their "annual pay increase" brood.
The family, with a father, mother and children, is the bedrock of society. Remove it, and you have a house built on sand. This is, of course, greatly exacerbated by a society with a "gun control" regime, where the criminals disproportionately survive, and the law-abiding disproportionately die. It only takes three generatins for such a society to turn into a jungle. As we have seen in Chicago, Detoit, and many other places.
Because they are substituting themselves for God. Their do-gooding is not a road to liberation (putting people back into direct reliance on God to make their own choices before Him) but to political dependency.