I'll take a crack at this...I don't think I can do any worse than the others ;-)
I would agree with djwoodworks that this sounds very much like a convention of Jehovah Witnesses, perhaps an assembly where you've been "marked". They deemphasize Jesus immensely... I've always said that if Jesus had given his model prayer at one of their Assemblies they would have pulled him aside and scolded him for saying "Father" instead of "Jehovah".
However the message is a bit off for them. The only "needy" the Organization appears to realize are those without a Watchtower magazine in their hands whereas I get the idea from your post the "needy" might be more traditional: those in need of food, clothing, or shelter. Also they won't tell you the name of their Organization, whereas JW's are always touting it.
The fact they wouldn't tell you outright, and the tendency to jostle you around while attempting to focus in on them with a picture, and the fact they were hiding behind a "mask" of positivity, leads me to believe it's not an outside church at all but perhaps a movement inside the church, one gaining adherents but not ready to divulge itself as yet.
It would certainly explain that smile.