I can think of at least 2 churches that feed hundreds every weekday, 4 that feed hundreds every weekend, many others who walk around with wagons and food, several clothing closets, and likely a great. deal I am missing... right here in the city I live in.
I found this to be the case in most major cities in The United States with few exception, and even then not a totally absent presence, Christian organizations doing this.
There is a food bank as well in my city, and it tends to operate out of church pantries.
The Christians in my city help the homeless, low incomes, single mothers, orphans, etc.
The work is getting done.
The point I am trying to make is that the vast majority of real charitable organizations I know of that I can actually see doing these things are Christian.
That isn't to say there aren't ones that aren't. There is a particular charity in my area that has done a great deal of good for kids living on the street that is not a religious organization. There are a lot of people who work in that organization that do so because they are Christian though.
Doing these type of works are buikt into the Christian faith. There are some protestants that incorrectly believe that you are saved only by faith, but it is well understood in Orthodoxy that faith and works are inseperable from eachother. Not that we are saved by works, there are no works that will save you, but that if you have faith the works come naturally.
I feel very compelled to do good for the homeless and disadvantaged, and it is not a certain time of year for me, it is an all year thing. There are many who come to volunteer and help around thanksgiving and Christmas, but there are 10 other months of the year, and loving people is more than a quick conversation and a gift.. it's an ongoing relationship.
And that is what Christians are supposed to do. Love people. Help people. Not because they deserve it, in fact, no one deserves it, but out of love. I say this because wicked entitled people like to accuse Christians and guilt them into giving. Charity dooes not come from guilt, it comes from love, and charity by nature is not an entitlement.