Obviously there are occasions on which even I find myself exclaiming 'FFS' or worse, when faced with a particularly adventurous interpretation, but on the whole, this amusing graphic is utterly wrong. It's like this:
It doesn't matter what the author thinks.
He or she may be dead, and is certainly not present at your reading. You have a complicated and rich cultural context which isn't the same as the author's, and so you'll interpret things differently. Good authors know this, and are fine with it. Bad ones work extra hard to make sure you see things his or her way. It doesn't work, because bullied readers rebel or give up.
A decent teacher wouldn't talk about what the author meant - they'd talk about the possible interpretations of the words on the page.
I hope I've successfully ruined the joke now. Further reading: 'The Death of the Author' (Roland Barthes) and Susan Suleiman's Authoritarian Fictions.