That's like, Dating 101, though? I'm not holding him to a standard as a nobleman. I'm holding him to a standard as a human being.
Your argument holds, as far as her being an innocent victim of Sedin being forced to take her to the ball.
But otherwise? He never wanted to take her to the ball.
What he should have done, is go to the ball without anyone.
Otherwise? This whole dating thing, though. When I grew up, I can't remember there being a codified system of going out with people without feeling, and having expectations of anything. So the Angloamerican dating concept hasn't been all-pervasive. Sure, in my youth, if I did something date-like (movie, meal, dancing, concert, art exhibition, whatever), I would also be courteous toward/talk with/show interest for/etc. my "date", but I wouldn't have "dated" if I weren't in some way romantically interested in that person.
At the same time, of course I've seen tons of people who were obviously out just to snag someone to have a quick roll in the hay with, wholly devoid of feelings, romantic or otherwise.
It feels like there are a bunch of expectations made, which presuppose an Anglosaxon (well, USofA) interpretation of how romantic (?) interactions with people should work. I'll agree with your standards as a human being, at the same time as we might consider how different a non-mass production, magical, quite socially stratified, etc. society might be from what a Dating 101 society might consider the norm.