Though he’s not much for superhero comics, Marc Sobel gets the joke that inspired so much “righteous, nerd rage”:

“Ultimately, the Joker’s rebirth is a physical manifestation of the
creative process… accompanied by a profound sense of disillusionment that none of it
matters, for the cycle will begin anew before too long…. The ultimate irony, of course, is that Batman has not been
granted such self-awareness, and, as the Joker points out in his
endless frustration, all he wants is for “the goddamn Batman to finally
get the goddamn joke.'”