That's certainly a sexist comment. She must want that quota system for the SCOTUS: the Jew seat, the black seat, the woman's seat, the inevitable Mexican seat, etc. I'm sure in the future someone will get the bright idea for a Muslim seat. I hope I'm dead by then.
Actually, I think the thrust of her complaint concerns something like proportional representation. Following that logic, most of the court should be Christian. And, of course, any ethnic group constituting less than 11% of the population should have no seat on the court since that would unfairly exclude representation of a larger ethnic demographic. This, of course, would mean no Jews on the court -- at least, according to O'Connor's dubious logic.