That chart would be better labelled, “Determining Obesity TODAY.”
The standards keep changing according to prevailing fashion.
Many people that are fit, still fall into the overweight chart. I just checked my husband’s weight/height ratio and he would be listed as overweight, yet he exercises everyday and doesn’t have an inch of fat on him. Muscle weighs more than fat, so a well muscled person will appear to be overweight according to that chart.