It might also have something to do with insisting on having one BMI for both sexes. The healthy percentage of body fat is higher for women than for men. The average height of women is less than the average height of men. Basing the BMI on the square of height, rather than the cube does provide a crude means of adjusting for the B.F. % differences between the sexes.
That only works out for average height men and women. As you point out; the BMI discriminates against taller people (of both sexes); which is really unfair, if insurance rates are based on the BMI.
It's long past time to switch to a direct % body fat measurement — which you can get these days from a cheap bathroom scale.
I don't know about the bioelectrical impedance sensors on the scales. I went through some effort trying to find a good one. I read that the measurement is affected by gender, height, and age, so I got a scale that had you enter all that data. It can swing over 10% within a day, and is often 15 to 20% higher than other measurement methods.