yes, however it should be the case that people give freely.
But that's the problem. People don't freely give enough. Voluntary charity is wonderful, but it's inadequate to meet the needs. Example: Suppose we relied on charity instead of tax-funded Medicaid to cover medical costs for low income persons. Here's some 2013 data:
Total 2013 Medicaid spending: $449.4 billion.
Link.
Total 2013 charitable giving: $416.5 billion. (And this was a record high.)
Link.
So if every cent given to charity was used for poor people's health care, there would still have been a $30 billion shortfall. And no money would have been available for disaster aid, education, scientific research, support of churches, and all the other things charity is used for. It's an utterly naive fantasy to think that if the tax burden were reduced, a social safety net could be maintained by voluntary donations. It's never worked before in an urbanized society (think of Dickensian London.) Besides, by it's very nature, charity is fragmented and unsystematic. There are 1000s of charities, each doing their own thing, with no way to organize how the funds are distributed. And charitable giving can be significantly affected by economic cycles. Downturns reduce tax revenue, too, but not to the degree voluntary donation is. Which makes matters critical. During hard times, when folks need help the most, there's less money available.
You know that's one of the main reasons Social Security was enacted. The Great Depression especially devastated the elderly. Even if they could find jobs,many were physically unable to work. And their families were also unemployed and couldn't help them. Charities did what they could but were overwhelmed. The only solution was a publicly funded old-age pension system.
The proper role of charity is to supplement and complement the social welfare system. It can never replace it.