And the fact is that things are pretty damned good in this country. You wouldn't have to go very far back in time to find an era where the very notion that the biggest health problem facing the impoverished would be obesity would be considered ludicrous, unimaginable fantasy, and yet here we are. It's pretty hard to go hungry in the United States; one can feed oneself quite well here (on food made for humans) on very little income.
But there are still some who need help, and private charities do a much better job of helping them than government programs do. Furthermore, Americans as a people are unwilling to see citizens suffer from poverty, and Americans as a people regrettably have the legal authority to institute those inefficient (and, to the extent they rely on seized money, immoral) government programs. If we want to avoid having the government arrogate more and more authority to itself, it behooves those of us in a position to be charitable to be charitable.
Sneering at the hungry merely helps to perpetuate a stereotype of conservatives as cold-hearted.