People denying that BMI is of any use whatsoever is part of the problem, too. Yes, it's not a perfect tool. Nothing would be.
But the people saying they dislike BMI as a measurement are rarely the "muscular rugby players" which are constantly trotted out as examples.
So many people on this thread saying BMI doesn't apply if you're muscular. Well, I had a look at the stats of the most muscular women I could think of, off the top of my head:
Caster Semenya, 5ft 10ins, 10st 10lb. BMI 21.5.
Jessica Ennis-Hill, 5ft 5ins 9st. BMI 20.
Laura Trott, 5ft 4ins, 8st 2lb. BMI 19.5.
I don't think carrying muscle is really the issue for most people with a BMI of 30, or even 25. It's easy to convince yourself otherwise - as I said upthread, I did, for a long time.
And BMI has a very broad range. The upper end of a "healthy" BMI is 11st for someone of my height, the lower end less than 8st. Is it so difficult to believe that, ideally, most women of my height should weigh within three stone of each other? That more than allows for differences in muscle mass. And I'm quite embarrassed to say I'm heavier than Jess E-H, despite carrying far less muscle than she does!