Laser I don't know what the right approach is either, but as the mum of a daughter (and a son) I spend a lot of time trying to work it out.
I would like to say though that I didn't call the OP grotesque, greedy or unwomanly, and I didn't think it either. It's not always implied...(I do understand the point you are making though, but sometimes people project things that aren't there)
Mango Thank you.. I wouldn't say it's entirely under control, I don't think these things ever go away, and they tend to recur at times of stress.
I'm not speaking to anyone from a position of moral superiority, but I do do a lot of reading in this area and a lot of thinking about it. Which does put me in a position to counter specific dangerous myths (such as being overweight is more healthy) with recent, large-scale scientific research.
What you look like in a bikini or what size jeans you wear may be trivial, but I think things like the likelihood of developing cancer, cardiovascular disease, and dementia really matter to us all.
I agree with you that long-term anorexia and bulimia is very damaging for your health - of course. I am not recommending it! 
I disagree with this though:
Good muscle mass & a healthy fat mass is likely to tip a person toward the higher end of healthy or just over, and the benefits from the strength & resistance training that give this outcome are immense.
People have posted upthread that very muscular athletes such as the Williams sisters and Jess Ennis have BMIs around 20-22. I personally do a lot of strength and resistance training and my BMI is 20. If I gain weight I never kid myself that it's from muscle. There are almost no female athletes whose muscle mass, rather than excess fat, puts them anywhere near the top end of healthy BMI.