Once you know their politics, does the religious affiliation of a Supreme Court Justice matter? I do think it is probably a statistical fact that first or second generation immigrant children are more likely the over achievers in school. (Start with the over achievers, then look at their demographic makeup, not vice versa.)
The second half of this piece is about evangelicals. I wonder what fraction of Protestants would describe themselves as evangelical. The piece doesn't say. If one looked more broadly within the judiciary, not just the Supreme Court, would this demographic pattern continue to hold?