When DC rebooted all of its characters in 2011, the video-game version of Harley paved the way for a new comic-book incarnation. Along with her new, revealing costume, two-toned hair, and bleached skin, Harley got a more victimized backstory. In this new version (not written by Dini or designed by Timm), the Joker threw his unwilling, struggling psychiatrist, Dr. Quinzel, into a vat of acid, dying her skin and warping her mind. For this Harley, love for the Joker wasn’t something she chose.
This isn’t the first controversy for the Joker’s best girl.
Source: Is Suicide Squad’s Harley Quinn the Most Divisive Character in Comics? | Vanity Fair