I imagine it also prevents theft if people are starving, especially if their kids are starving.
I have a friend that lost her mother. "K" and her boyfriend live on their own (he was disowned by his parents) they would probably be living on the streets or worst if it wasn't for systems like this. He works 2 jobs and had to drop out of college. He was only 12 credits short of his bachelors! I know there are thousands of cases like this. There are abused woman, single parents, abandoned teens, disabled minimum wagers etc.
Yes, in a perfect world the traditional family would be able to support the short comings of a member's obstacles, BUT the reality is plenty of families are broken. FDR realized the importance of social welfare -- I hate to ever use that word, because it often brings up negative feelings.
The way I look at it is no matter what the government is going to get their taxes SO I'd rather see it going towards health care and people in dire need, than pretty flowers on the road. Yes, there are people that abuse the system (it's wrong), but that's with anything. If you open up a grocery store there will be instances people steal; that doesn't mean we take away grocery stores! Some of my friends that are republicans just annoy me to no end.