As already pointed out, just because you are classified as having a BMI that is ‘overweight’ (according to WHO guidelines) doesn’t mean you are overweight. One case against Nintendo, it’s that the screenshot above of the UI doesn’t make clear that BMI is a very fallible measure, and that having an ‘overweight’ bmi doesn’t necessarily mean what it sounds like it means.
The article says:
"4-feet-9-inch-tall 10-year-old who swims, dances, and weighs only six stone. "
If these figures are true, her BMI would be 18.3 (underweight).
Her weight would need to be over 8 stone to give overweight.
If there was a programming error that miscalculated the BMI or a hardware error that misread her weight (badly) then I guess Nintendo could also be at fault. Seems unlikely to have such a basic error – either there’s an error and nintendo is at fault, or someone is telling porkies.