For whatever reason, and I guess this is mostly based on my experience with my Catholic friends and family, even if they are not lawyers the Catholics just love arguing about rules. Perhaps that's because Catholic Dogma and Tradition is complicated. In any case, I suppose that means it should be unsurprising that a lot of Catholics end up studying Law and as a result provide a wide pool to draw from when it's time to nominate Justices to the Supreme Court.