JeffT- I've pointed out what the churches have been doing for the homeless (among other things, but the homeless camps are a good example). You have countered that people don't need a religion to get together and accomplish good things. I agree they shouldn't need it. The trouble is, at least around here, they don't seem to actually DO something. There is lots and lots of talk, the problem gets studied from all angles and everybody agrees that we should give the homeless a home - in somebody else's neighborhood. The thing the churches do best is convince the faithful that some degree of personal sacrifice and/or inconvenience is necessary to do good.
I agree that on a localized, practical level, religion may very well serve to enable some people to do good works that may otherwise be difficult to organize. They key word is difficult, and not impossible.
Many things work well on a local level, (as the saying goes, think globally act locally), however realistically not all things scale well, and extrapolate linearly. On a large scale, (or the "whole", as the OP brings out), more harm is done than good by religion. One doesn't need look too far to back this up empirically.
d4g