BMI isn't always a dependable measure. Like any system, there will be exceptions. If they felt that she was in danger, it makes sense to check further and make sure that this little girl is okay. But common sense has to weigh in here somewhere. The truth is, she's just fine.
I'm amused and horrified that they discuss eating disorders without a trace of irony. The reality is, a second check would indicate that Chloe's weight is within normal bounds, and certainly not obese to the point of risking health issues. If her parents are accurate, she has regular exercise and eats healthy food. What red flag are they using to continue to insist that she is in danger?
Healthy weight isn't the ultimate end result. Healthy weight is the product of good eating habits, exercise, and balance. It doesn't do the person any good to reach an ideal weight if they do so by drug abuse, bad eating habits, or skipping food that also contains vitamins and minerals. All of these aspects are related, and to focus on weight alone skews the reality of treating the body as a whole.
Meet Chloe. Imagine being told she is so overweight she is in life-threatening peril.