I would be surprised if it did as well monetarily standard index funds, though that would be rather beside the point. The set of companies in which a morally aligned index fund may invest is, by design, smaller than the set of companies in which an amoral index fund may invest, and so they may be intentionally passing over profitable companies.
One of my favorite quotations is from A Man for All Seasons, with Paul Scofield as Sir Thomas More. "If we lived in a state where virtue was profitable, common sense would make us saintly. But since we see that avarice, anger, pride and stupidity commonly profit far beyond charity, modesty, justice and thought, perhaps we must stand fast a little, even at the risk of being heroes."
One of my favorite quotations is from A Man for All Seasons, with Paul Scofield as Sir Thomas More. "If we lived in a state where virtue was profitable, common sense would make us saintly. But since we see that avarice, anger, pride and stupidity commonly profit far beyond charity, modesty, justice and thought, perhaps we must stand fast a little, even at the risk of being heroes."