But, yes, by all means, Batman boning a kid doesn't have any negative connotations. And you continue to double down on the "age of consent" / "legal age" hill, which tells me you're missing the point.
You calling her a kid seems to suggest that
you're missing the point, hence why I keep saying that.
She's NOT a kid. She's an ADULT, in her early or mid-twenties. Perfectly capable of making her own decisions and knowing they'll have consequences particularly with her considering she's usually portrayed as being above-average smart. The age difference between Bruce and Barbara going with how they're commonly depicted and how it's suggested in this movie while significant isn't greater than how a 25% of relationships in the US are made up according to statistics. She was the
aggressor in the sexual encounter, she made the
choice of kissing Bruce, disrobing, and proceeding with the sex. Their teacher/student relationship is an informal one so while it may be "questionable" for Bruce to go along with it it isn't inherently wrong. And the only reason why it's often discouraged in college campuses is because of the imbalance of power and the complications and lawsuits it could bring on the school. Not because of any moral or legal "wrongness" in it, just that it makes things more complicated. Same with workplace relationships often being discouraged, some places even making those engaging in workplace romances having to sign waivers to remove the workplace of any liability.
Now, we can agree on the writer having issues when it comes to his portrayal of Barbara and how the scene/segment of the movie was done but that's going a tad meta in terms of the narrative of the movie. In the narrative of the movie we now have to try and help it to make sense and determine if the lengths we have to go to in order to do that are too much. A suspension of disbelief process.
What we know is that we have here two adults who work closely together every day/night and have known each other for some years. Their daily encounters usually involves some sort of physical activity with physical contact, when Bruce trains Barbara. Both are sexually mature and are within an age difference that's socially acceptable under most circumstances. (Again, 25% of marriages in America have at least a 6-year age gap between the them with the man being the older on, this jumps to nearly 33% when we expand the age difference to at least 4-years.) They're under no official or formal bindings that forbid them from having a physical relationship.
Given that Bruce
is her teacher is it wrong? Perhaps.
Should Bruce have stopped it because Barbara was clearly starting it due to her intense emotions? Probably, yes.
Should he not have done it out of respect to Gordon? Certainly.
After doing it should Bruce have called/talked to her the following day or had not avoided her calls? Certainly.
But, he didn't. Surprise, a man who dresses up as a bat and beats criminals to within an inch of their life every night doesn't make great decisions and gives in to his base emotions and desires.
I didn't find the encounter all that wrong, as Barbara says over the phone; "It's just sex, why does it have to be such a big deal?" She clearly didn't regret the night and doesn't think of sex as that big of a deal. Bruce was obviously struggling with his feelings on it.
Yeah, it was inserted in the movie poorly, handled poorly and it didn't tie into the the actual TKJ part like, at all, (hence why I think there should have been a bed-side heart opening from Bruce to go along with the other changes they made to that part of the movie; which there were quite a few that I see now that I re-read the book last night.)
But, there it is. In the end, flawed characters made a bad decision, people in the real world do it all of the time and usually under far less acceptable circumstances.