As others have said, it’s not about religion it’s about ethnicity. If you really wanted to skew things, look at Ashkenazi Jews versus everyone else. You’ll find the former group extremely over-represented among Nobel laureates, Fields medalists, Turing award winners, and world chess champions. In light of all these achievements, I think it makes sense to distinguish Jews from non-Jewish whites at Harvard, where the achievements are paralleled there as well.