You can just write anything you want about superheroes. They're fictional.
Batman's listening to ska 24/7. You can't argue with me, he's made up. I made this up.
He's got an earpiece in all the time, and you know he's streaming third wave ska. He's a rich white guy, he's really into The Toasters. His playlist is a mile long, and he picks spots on it to start depending on what he's doing at the time.
It's why Joker is obsessed with him. Nobody gets that close to Batman, but Joker does because he's a creepy weirdo. He shoved his head against Batman's one day, smearing greasepaint on that cowl, and he heard "Skaternity" and his giant dimples twitched like cat whiskers. No one believes him. Harley doesn't even believe him. Joker wants to smoke a huge bowl with Batman and listen to The Maytals but Batman is always busy... punching the Joker.