Look up any hospital in America that is older than 40 years old. It was, no doubt, started by a Christian organization. The same is true of universities.
The irreligious, those who simply shrug their shoulders at spirituality, have done secular altruism all along the history of the USA. The active nonbeliever and the ardent atheist have largely NOT done altruism in our history. It wasn't a priority for them. There were a handful of these folks who donated, but no organization of them acting in a beneficient manner.
If Christians were to stop performing altruistic acts in America, then there would be countless problems among the impoverished. Are you aware that 1 in 5 Americans lives under constant poverty today? If Christians paused even for a month, there would riots in the streets due to pervasive hunger and homelessness.
Look up the local food banks in your area. Chances are they were organized by churches. Look up clothing closets...same thing, organized by churches.
Altruism need not be conversion linked to altruistic acts. Go to any church of any medium or larger size and witness the number of secular meetings that go on there. Without those places, those Al-Anon, Narcotics Anonymous, an endless variety of abuse and battered wife groups, medical diseases and ailments of all kinds, would simply not have a private place to meet to would offer the necessary anonimity.
If you doubt this, merely open up a newpaper or visit websites and see where they meet.
Many churches donate 10% or more of their tithes and offerings to outside secular nonprofits. Go to a rent assistance group in an urban area and ask where the donations come from. Chances are high that it's from area churches.
I have to shake my head in dismay that this is not understood to be essential to cities. Without Christian altruism of secular groups and people, those cities would flounder as the tax base is insufficient to handle their needs.
