It's because the bar for being medically obese is actually pretty low to what we think. Guarantee if you stood next to someone with 18% body fat you'd notice a difference.

BMI was created to study populations, not individuals. It's a joke that doctors use it as a diagnostic tool because medically speaking a 5'10" 220lb NFL running back with 11% body fat has nothing to do with a 5'10" 220lb couch potato with a 42" waist.

What's seen as far around is morbidly obese by medical standards. BMI 40+. You've got about sixty pounds of runway left.

If body fat proportion is typical (ie not athletic) it’s probably pushing up toward 30% and in the normal world it’s getting up there. Of course to our perverted eyes it barely registers, so just enjoy the thought for now that regular (especially trim) people are likely starting to notice.