I believe that's true. But I don't think being disbarred by the Supreme Court prohibits a lawyer from practicing law. It simply means he cannot appear as a lawyer on a case before the Supreme Court.
I remember something about that incident that struck me as, "well, who cares then." Most attorneys never appear before the Supreme Court, so most aren't qualified to do so. They still practice law, but wouldn't be able to try a case beyond the jurisdiction of their state courts.