Honorary and courtesy titles are an old custom. Like calling the heir to a noble title “Lord” such and such even though he was in fact a commoners eligible to sit in the House of Commons. But just think:”Mr.” used to apply only to gentlemen. Someone else was just Tom Brown, or in medieval days before patronyms became the usual. just “Tom”. Not too many years ago, whites in the South never referred to a black man, even a doctor or lawyer as Mr. or Dr. but just called him “Tom” or “Brown.” A strange black man, even an old was was called “boy.” Nowadays, of course, the politicians are our gentry, so they get called by the highest office they have held. In the 19thcentury,” Judge”was frequent and a prized title. Stephen Douglas was more often called “Judge Douglas” than by the title of Senator, and he liked the idea.