Mary Sue’s have always been with us in one form or another.
The first one I can recall running into was Harriet Vane. She was a mystery writer in the Peter Wimsey mysteries by Dorothy L. Sayers. Vane was created and inserted because Sayers had fallen in love with her own creation, Lord Wimsey.
You can undoubtedly think of many others yourself.
But this new breed of Mary Sue…The Social Justice Mary Sue is something new and a lot worse.