In the run-up to Halloween, I've seen really young girls dressed up as Harley Quinn pop up on social media. Confession: It grosses me out when I see it. I get that Harley was the best part of the Suicide Squad movie and is on a lot of merchandise nowadays. And, like lots of superhero characters, she has facets that let different sorts of people love her for different reasons. But Harley Quinn is a character who's all about dysfunction. She is what she is because of an abusive relationship with a messed-up killer clown.
When she was first introduced in Batman: The Animated Series, she was essentially a fanatically devoted gun moll. The character's throwback performance and her Looney Tunes-style approach to violence won viewers over at first blush, and the troubled nature of psychiatrist Harleen Quinzel's relationship with the Joker added unexpected depth to Harley's development. She had smarts, quirk and layers, eventually becoming one of the most popular additions to Batman lore.
Even if you think of Harley as a symbol of survivor strength, she only gets there as a result of having gone through the hell of a romance with the Clown Prince of Crime. (In current DC Comics, she's being played as a goofy, randy antihero.) The only version of Harley that doesn't have that at its core is the all-ages DC Superhero Girls iteration.
But most of the kids I've seen dressed up as Harley aren't done up as that version; they're doing the Suicide Squad movie's take on her. Granted, she looks cool, acts brash and kicks arse. Still, if a young kid starts asking questions about the character whose look she's wearing - and, as a father of a kindergartener, I know that they will keep asking and asking - eventually you're going to have to field questions that touch on the ickier parts of Harley's history.
I'm not saying it's impossible or inadvisable to sanitise Harley for younger minds. But, even if that does happen, the character's history - especially as executed as in Suicide Squad - still makes her a bizarre costume choice for young kids.