I can't speak for com2kid, but I am alleviating suffering around the world by working hard at my (not particularly shitty) startup job. The amount of money I give to charity is an approximately-constant fraction of my income. If I work harder I'm more likely to get paid more (and, unless I work so hard as to be
less productive overall, which is certainly possible and a very bad idea, my employer is more likely to be successful and make my options worth something), so the starving billions get more money from me.
I don't think this situation is all that unusual. Charitable giving that's a fixed fraction of income is common practice in many religions (which have a whole lot of members) and among the "effective altruism" community (which is small but I bet it's overrepresented among HN types), and is a natural enough thing to do that I bet lots of other people do it.
(Ideally I wouldn't need to say these things explicitly, but I will anyway: Of course working harder is not always a good idea; as I said above, it's very much possible to work harder and merely make yourself tired and therefore less effective. And of course working harder, whether it makes you more effective or less, is no guarantee of getting paid more; plenty of employers are quite unresponsive to their employees' commitment and productivity. If anything I've said above looks as if it's denying those things then I expressed myself badly and I apologize.)