You would expect the majority of pretty much anything to be Christian.
A 2017 Pew Research survey found that 18% of Americans consider themselves "neither religious nor spiritual" and that a further 27% consider themselves "spiritual but not religious" [1]. In total, roughly 45% of Americans consider themselves "not religious". Given the historical trends in the U.S., I suspect these numbers are even higher now.
https://www.pewresearch.org/fact-tank/2017/09/06/more-americ...
The internet, and Reddit especially, are a self selected group that don’t represent the majority of the 330M people living here at all.
Distance between what's written in the comments and the reality I personally observe, is the dimension I was thinking of.
Most people in the U.S. identify as Christian.
In my shoestring travels around the U.S., I'd say most of the help I received was from people who identified as Christian.
I also observed that most charity work like feeding people regularly is done by Christians and other religious/spiritual groups.