If you look at it as a poll of the generosity of various sects of religions, then it looks like the atheists and agnostics and Buddhists are the most generous. But then we interpret it to favor our own identity. We might say, look the agnostics and atheists are the most generous, but the Buddhists might say they're proportionately the most generous because there are far fewer Buddhists than atheists and agnostics. But it is disturbing how little the Christians gave.
If I were to stumble across him I'd probably have to distribute the money more evenly. I put some in for the Buddhist, some for the spiritual, and some for the pagan, and I'd have to put some in for the Christian just to make them look a little better. That homeless guy would love to see me coming.