Are the lines between social classes really so clearly drawn that she could barely say two words in her own defense? If an Equestrian noblepony dared to talk down this way to a commoner on the street, they'd probably get a hoof to the jaw for their troubles. Only gentleponies could duel, true, but try and catch a commoner for an assault when the mob protected its own against one of society's upper crust. Not that anything like that happened with any kind of regularity 'upstairs' -- but it did still occasionally happen.