You're correct that the largest share of giving goes to religiously-affiliated organizations, but the idea that the largest shares goes specifically to megachurches seems unlikely to me. If you've seen this reported somewhere I'm primed to change my mind.
And I don't think it's totally fair to exclude religious donations as somehow "not valid", especially in the context of the critique that Americans don't value community with each other. Religious charities tend have less access to alternative funding sources, so rely on these donations more. Note: I'm very much not religious.
> A fair amount of the rest goes on political lobbying and influencing.
I get a little mixed-up on whether donations to non-tax-deductible non-profits "count" in the metrics (e.g., does my donation to the ACLU which has a lobbying arm count just as my donation to the ACLU Foundation which cannot be used that way?). Nevertheless, I think it's wrong-minded to discredit charitable giving to organizations that influence public policy given the multiplicative impact that policy has on the lives of people and communities. Some of the biggest impacts to the lives of people came out of organized efforts to influence policy.
> If the US wasn't "individualism run amok" it wouldn't have tent cities of homeless people, and its health industry wouldn't be bankrupting half a million people a year.
This feels like a pretty uncharitable and over-simplification of very complex issues that also get into inter-state dynamics. I also think there's an error made in treating US culture as some sort of homogenous cultural construct. More than many other countries, the US is constantly at war with itself culturally.