> harmful

It's hard to conceive of anyone meaningfully "harmed" by being a BMI outlier.

The only real occassion it comes up is when some lean and uncommonly athletic person gets miscategorized as obese and get warned of increased risks to their wellness if they don't lose weight. A warning which they generally laugh at because they know their own situation.

That's hardly "harm" -- "mild social nuisance" is more apt.