No shit, of course I know that. That doesn't mean doctors and pediatricians don't use them somewhat still, and somebody who is full of muscle mass that makes them "obese" will still be considered "obese." And obesity only became such a fucking huge problem because our culture perpetuates this ideal of thinness that most people cannot even hope to achieve, while showing commercials for BK and McDonalds and diet pills. And then we have the insurance companies who came up with the fucking weight charts, and they are the ones who came up with stupid correlations to suggest that body fat = omg you're gonna die.
Body fat is a good thing, and it usually isn't gonna ENDANGER YOUR LIFE, even if you are obese by the standards of having a ton of body fat. Body fat is there to protect you and it keeps you from getting diseases, you recover from cancers better, you are protected from some cancers as a woman, and the amount of body fat you have doesn't determine if you get high cholesterol or heart problems--your fucking shitty diet and lack of exercise does. And if you changed those two things and still weighed enough to be obese, you could be as healthy as somebody who is lightweight and exercises regularly.