Like Smokin Joe, I also attended both parochial and public school. But my assessment is different than his.
First let me say, I think perhaps there are the number of Catholics on the Supreme Court for in part no other reason than coincidence. That plus the fact that all these people are very disciplined in how they conduct themselves. I do believe that was one of the benefits of attending parochial school, being disciplined.
In terms of quality, I thought parochial school was deficient to that of public school. I grew up in a mixed suburb, having both blue and white collar. In attending parochial school, and I went there for grades 1 - 8, and there were no advanced math, no algebra, geometry, etc. There were no languages to study but English. There were no sciences like Biology, Chemistry, etc. So in the sense of courses of study for one interested in learning, the parochial school was no contest to the public school where I resided in Pennsylvania.
My son, my oldest child, went from K - 12 in the public school, within the same community I grew up. When he completed 8th grade, he completed Algebra I & II and Geometry, he studied two years of languages. I had none of this in parochial school. When he graduated high school, he studied Latin for five years, he exhausted all math courses, all science. He had 2 years of Biology, 2 years of Chemistry, Physics, and a number of college courses before he left high school. I did not have the opportunity to study what he did and advance as he did with my education in parochial school. And believe me, I would have benefited from that!
Bottomline, I think it shows that it just does not matter what religion one is on the Supreme Court. It is the ability to think objectively and adhere to the Constitution along the way.
I agree that less ivy league education would be better. Again, some diversity is not a bad thing. Too much elitism in America to suit me.