Let's not forget that rape is heavily tied in with misogyny. People react more strongly to hate crimes than mundane ones. Only a small segment of murders are hate crimes, but every rape is one. Even genocide isn't generally a hate crime in a comic book context - Black Adam and Cheshire and Joker aren't racist, they're psychopaths, and their victims are dead because they were in the way, not because of any inherent trait. Light's victims get raped because they're women, which hits a very different part of the reader's psyche.