As for the philanthropist, I think the relevant heuristic is that we approve of anyone who saves lives, to socially reinforce the urge for others to do so. If our instincts developed in a tribal environment, then saving a life, or a small group of lives, is the best that anyone can realistically do, so we had no need to scale our admiration to a larger scale.

But if we are to become less biased, and disdain the philanthropist who spends his life-saving money inefficiently, we should be totally consistent about it, and disdain far, far more those who could spend money to save lives and don't (unfortunately, that probably includes most of us).