The Killing Joke has enraged Batman fans because Batman and Batgirl have sex. It does not come across as a romantic scene. It seems more like a teacher (Batman) taking advantage of a young student (Batgirl). She is giving him sex to try to gain his approval, not because she actually wants sex.
In some ways, Batman even seems like a classic sexual predator. He is taking advantage of a girl 20 years younger than him. He only deals with her in his “authority figure” mode. Batman knows that Batgirl is really Barbara Gordon, but he never lets her know that he is Bruce Wayne. In other words, he knows her vulnerabilities, but never allows her to see his. This is classic sexual predator behavior.
Historically, many older men have used their positions as “coach”, or “professor” or “boss” to coerce a young woman into sex. The superior/inferior relationship can be seen by the mere fact that he is known as Bat MAN, while Barbara is merely Bat GIRL. The fact that she does not call herself Batwoman, shows that she has unconsciously accepted her status as inferior to her male counterpart.
When they do have sex, it is on a dirty rooftop, with Batman still wearing his Batman mask. He could have taken her back to his sumptuous Bruce Wayne estate for a truly romantic encounter. Instead, the sex reinforces that Batman is the master and Batgirl is servicing him
Batgirl having sex with Batman
Even after the sex, Batman still does not give Batgirl the approval she so desperately needs. After the sex, Batman never calls, never asks how she is, and never shows any sort of tenderness towards her. In fact, Batgirl ends up calling him, still desperate to get the recognition she desires from her teacher/coach. This is also classic sexual predator behavior. By withholding his approval, the sexual predictor can continue to coerce the young woman into giving him favors to gain acceptance.
Batman comic fans have gone beserk on the internet because none of this “sex with Batgirl” plot was ever in a Batman comic book. The odd part of The Killing Joke is that the the second half of the movie follows almost frame for frame a Batman comic book episode in which the backstory of The Joker is revealed. Once this story line starts, it is as if the first half of the movie never happened. It is like watching two unrelated movies.
Most fans have agreed that the best thing to do with The Killing Joke is to just pretend the first half of the movie never happened. Some have gone as far as recommending that you fast forward through the first half of the movie without even watching it.
Unfortunately we did watch it and now will never be able to look at Batman exactly the same way again.