It makes no allowance for muscle mass, just assumes you are heavy with fat.
My cycling coach is 6' 210 pounds, so according to the chart he's overweight, at risk. So how does he qualify for Olympic Trials and UCI Worlds, and beat Marty Nothstein in the keiren at 2002 Elite Track Nationals?
I could shed a few pounds now (about 25), admittedly, but I'm not 17 any more...