Also known as The Clown Prince Of Crime and the Harlequin of Hate, The Joker has been the arch enemy of the The Batman since almost the very beginning of the Dark Knight Detective's career. First appearing in Batman #1 in April 1940, The Joker was originally a comic figure no different than any other colorfully costumed criminal bank robber. In time, however, he would grow into a symbol of the chaos that threatened Gotham City much as Batman was a representation of strict order.
Related: The Complete History Of The Joker
The petition was posted on the free hosting site Change.org. At the time of this report, it has acquired 338 signatures. The petition asserts The Joker was portrayed as homosexual for at least half of his 80-plus years of existence and that Batman: The Animated Series "retconned his homosexuality" by introducing Harley Quinn as a love interest.
The petition cites Frank Miller's interpretation of The Joker in The Dark Knight Returns, Grant Morrison's interpretation of the character in Arkham Asylum: A Serious House On A Serious Earth and the opinion of legendary Batman artist Neal Adams as precedent. The petition also makes mention of behaviors The Joker engaged in that are "stereotypical" but paint a "very clear picture." Specifically, that The Joker "... has many feminine traits - he uses lipstick, paints his nails, wears high heels and sometimes does crossdressing."
To call the arguments made by this petition questionable would be a understatement at best. The fact of the matter is that there is little textual evidence as to The Joker's sexual orientation one way or the other, so there is no way to make him "gay again" when there's little evidence he was ever gay in the first place. There is just as much evidence that The Joker is asexual or that any sexual advances he made on Batman were meant to be jokes. Additionally, both Miller's and Morrison's stories are Elseworlds - comics set in alternate realities outside of the main DC Comics universe. And while Neal Adams is a prominent Batman artist, he is but one of many and he is not The Joker's original creator.
Instead, it seems possible that this petition may be an effort by trolls to tie one of fiction's most famous serial killers to the ancient stereotype of homosexual men as predatory creatures. It seems dubious that any LGBTQ comic fan would quote the notoriously homophobic Frank Miller's take on anything as the gospel truth or that they would so casually dismiss Harley Quinn as a beard for The Joker, given the character's own long history as a LGBTQ icon. The only certainty in all of this is that this petition seems unlikely to inspire any drastic changes at DC Comics one way or the other.