I don't know these people, but ... neither do you. Perhaps they are deserving of all the hypocrisy you are crediting them with, or perhaps not. Maybe they did talk to that man before or after you showed up on the scene and offered him some aid, or maybe not. Unless you were there the whole time you just don't know. But just because someone doesn't give how or when you think they should doesn't mean that they aren't.
I'm a mormon and I very much relate to that sense of community and the accompanying duty to it you mention, but you'd be unlikely to see me giving money to someone on the street (although there are times I have) for multiple reasons. To start with, my community has an extremely high drug presence and personally I'd much rather support the local soup kitchen where I know the money will go to help feed those who need it, rather than paying for someone to get high. In addition, I very rarely carry any kind of cash on me these days so without actively planning to have money on hand in case I run into someone, I honestly can't. As things are, I prefer to donate my time and money towards programs that aim to not only give a man a fish, but also teach him to fish and where a good fishing spot is and maybe loan him a boat to get there as well. My local church is always running some sort of food or item drive geared toward the specific needs of our area (and there are a lot), but walking by the building you're unlikely to see any of that. But just because you don't see something in passing doesn't mean it isn't there.
So when I look at that picture I find it ironic and sad, but it's a frozen moment in time with no before or after, unlike the people in it. Calling them out for not doing what you think they should have is something that should have happened in the moment when you had the opportunity to get the whole story, and when it perhaps could have done something to help. After the fact...what real purpose does it serve? It doesn't help that man in the picture, and just adds to the bitterness on both sides of the religious/non-religious divide.
Edited to add: And this isn't to say that hypocrisy shouldn't be called out - because it should! It's something that I think everyone has to watch out for. But calling someone out for hypocrisy through the internet when it's unlikely they'll ever run across it just seems pointless to me. If you're going to do it, do it in the moment when there's a chance that you'll actually be able to influence them and make them rethink their actions. Or perhaps they'll share the story behind their actions and you'll get to be the one rethinking. Either way, it opens the door for communication rather than slamming it shut with a quick judgment that may or may not be accurate.