Yes, it could possibly agitate the problem, but I believe the problem shouldn't be there in the first place. A girl with a fragile self-image should trust her parents' or doctor's opinion of healthy weight more than some random video game she played.
I agree... and disagree! If a girl has a fragile self-image, she can't necessarily rely on the opinions her doctor or parents. Especially not when she would place more weight with her peers and the media. At that age, those things can have an awful lot of pull.
I'm not blaming the girl for this, since it's not her fault, but it's certainly not Nintendo's or BMI's fault that this situation exists.
Absolutely, but that doesn't mean they don't have to do anything about it. For example, it's not Google's fault that there's porn on the internet, but it still introduced safe search, because it knows that's a more fruitful course of action that attempting to clean the internet. Not that I'm really suggesting a specific course of action for Nintendo, because I would put this down to a one-off glitch with the hardware. Having said that, a parental control to remove the BMI function might be something worth thinking about (I've not played Wii fit... maybe that's integral to the game?).
But then, where do you draw the line? You can't bow to every single complainant about every little thing.