Bruce Timm's reasoning for the sex stuff and was probably Brian's idea, basically Batman and Barbara are flawed characters who don't understand relationships:
http://www.vulture.com/2016/07/batman-the-killing-joke-sexual-violence.html
I'm guessing there will be a lot of conversation after the movie's release about the sex scene. At what point in the creative process did you come up with that idea?
It came from a three-way conversation between [co-producer] Alan Burnett, [screenwriter] Brian Azzarello, and myself. I don't remember who initially came up with the idea, but we all kind of jumped on it all at the same time and said, Yeah, that's kind of where we need to go. My memory kind of says it was Brian, maybe, who came up with the idea. But I'm not sure.
But why include it? The two characters have a pretty strong father-daughter-ish relationship bond by that point, not a romantic one.
We were aware that it's a little risky. There's definitely some stuff in that first part of the movie that's going to be controversial. Here's where we came down on that specific issue: It was really important to us to show that both of the characters make some pretty big mistakes. I mean, his “parental skills” aren't that great. Maybe never having had any kids of his own, he doesn't realize that if you tell a kid to not do something, they’re going to want to do it even more. And then she makes some mistakes and then he kind of overreacts to her mistakes and then she overreacts to his overreaction. So it's very human; it's a very understandable story. It's tricky because it's messy, because relationships are sometimes messy. But to me and to Alan and Brian, it was all very fascinating to us to explore that angle.
What kind of reaction are you hoping to get from the viewers?
I have no idea. I mean, I can kind of predict. Some people are going to be just freaking out, and some people might be going, Okay, I can see that kind of makes sense. It's not a comfortable place to be, but … We'll see.
They were aware of Barbara being the women-in-refrigerator trope in the original comic, which is why they had these additional 30 min to expand on her (but it seems to have failed):
When in the moviemaking process did you all realize you needed to change the way Barbara Gordon is depicted, in contrast to the original story?
It's a little complicated. This was actually the third time that we had tried to do The Killing Joke as a movie. The first couple passes we did were going to be just the story from the comic, and we knew from the get-go that the source material wasn't long enough to support an entire feature. Our original plan was to make it like a mini-movie — a half hour, maybe 45 minutes. But the last time it came up, we looked at it and thought, We should somehow expand it to a full feature length.
Knowing that we had that much time to play around with, we realized we didn't want to just pad the story out by adding a bunch of business in between all the different sequences in the original comic, so we thought, Hey, we could actually use that extra story length to address one of the issues that I kind of always had with the comic in the first place. Even back when I first read it, I was very aware that Barbara was basically there just to be maimed and set Batman off on his quest to find the Joker and save Commissioner Gordon. This was years before the term women in refrigerators was coined, but it's the classic woman-in-the-refrigerator situation, where the female in the story is basically only used as a plot device for the male protagonist.
So we thought, If we're going to add a whole bunch of new story, let's make it all about Barbara. We decided that it should be dealing with Barbara as Batgirl, so we can spend more time with her and kind of understand where she comes from. It let us spotlight the areas where she's a good crime-fighting partner for Batman, and some other areas where she's not quite a good fit because she comes at crime fighting from a completely different place than him.
The first 28 minutes or so are about Barbara, then the plot of the original comic kicks in. What links those two sections, thematically?
That's the tricky part of it. We deliberately tried to not really link the opening to the Killing Joke part explicitly. There was some discussion about that: Should we try to fold it into the Killing Joke part of the story more? Should we hint at the Joker in the first part? It's kind of an odd structure for a movie. It isn’t one long complete story. It really is two different stories with a break in the middle. We just decided that would be the best way to go with it. I honestly don’t even think of them as being one story. As weird as that may be. We just didn’t go down that route.
In terms of thematics: Boy, I don’t know. It’s probably going to take me years to figure that out. Often these things don’t hit me straight up. A lot of what we do is instinctual and intuitive. There can be deep, thematic resonances I don’t get until years later, when I go, Oh yeah, look at that, how clever we were!
As for viewing it as two stories, were you worried about that coming across as disjointed?
I mean, sure, yes. Here's the thing: The entire movie is a very odd movie. One of the other things that I always had concerns about in terms of adapting this story for a movie was that it doesn’t hit the traditional movie structure. There's not a grand, big, explosive finale at the end, and it ends on a really weird, ambiguous note. Batman never triumphs throughout the entire story. So if it's got this weird, strange structure where the first half doesn’t even barely relate to the second half, it’s like, Whatever — we’ll just do it.
Bruce Timm was mixed on the original comic but didn't want to change it too much:
Given that you’ve always been uncomfortable with the way Barbara was used in the original comic, did you ever consider getting rid of the sexual aspects of what’s done to her? Maybe just have her be crippled and leave it at that?
No. Like I said, ever since the comic came out, I've always been ambivalent about this particular story. It's not my favorite Alan Moore comic, especially compared to the other things he was doing back then, like Miracleman, V for Vendetta, Watchmen, Swamp Thing. It has always disturbed me and I made a real concrete effort going into this project: I’m not going to try to put my own "spin" on it. I’m not going to make it a Bruce Timm movie. Warts and all, the story is what it is. It’s kind of a classic. And as uncomfortable as some of this stuff is, it's not my story. I’m just the guy who’s putting it on the screen, so I didn’t want to change it and make it more palatable to my own sense of taste.
But I think it’s not as extreme as it could’ve been. We didn’t go out there waving a red flag like, Hey, we want an R rating! It’s horrible, but it’s relatively tastefully done, as was the comic. In this day and age, we clearly see way worse things. Even on prime-time TV, sometimes, on shows like Hannibal or even Gotham, in terms of explicit violence. We needed to stay true to the comic.