Maybe you can replace Clarence Thomas with Colin Powell and you might have an argument there.
Thomas’ career before his appellate appointment by Bush I was as a pretty piss poor politico. Assistant Secretary of Education for the Office of Civil Rights? Chairman of the EEOC? Can I yawn even more about what kind of legal skills those positions take. If you want to compare Thomas to Chief Justice Roberts (who was acclaimed by my fellows on the bar as one of the best litigators in front of the Supreme Court of this generation), he’s pure chaff.
Thomas is pretty silent during oral arguments and his SC opinions are pretty mediocre. Maybe he does believe oral arguments are unnecessary (as one of his biographers suggested), I just don’t think he’s an intellectual heavyweight compared with his peers. He wasn’t a powerhouse private practice attorney, never taught at a prestigious law school and never held legal positions as a US Attorney or with the DOJ. His resume is definitely (by a large margin) the poorest of any of the folks currently on the Supreme Court.