We overvalue prestigiousness of credentials and undervalue real world experience.
People who have been on the end of the failures of our social, political, and legal systems.
Yes, he's qualified. He's smart. But what in the human condition has he experienced that would give him a perspective the Court couldn't already consider?
In which case why even have 9 justices at all? What is the point of them deliberating and voting?
It symbolizes that he has a stunted view of parts of humanity that don't affect him and he isn't interested in expanding that view.
Heaven help anyone poorer than him, or a different skin color or a woman, who has to make heir case to him and any court he sits on.