I have to say I agree 100% with the OP. I myself am much larger than I should be, but when I look at the BMI stuff, it seems to indicate that I am nearly morbid.
BMI does not take into account anything other than height and weight. Consider that muscle weighs more than fat, and you can see that some overly active people would fall into the obese category simply due to muscle composition.
For me, I have plenty of both going on. Most people don't consider me fat and scoff when I suggest that I am. I don't look like the average 6'3" 280lb person because I am far from inactive and seldom eat crap food.
But in short, I agree with the article. Health is far less based on height/weight and far more based on activity. The 6'0" 160lb kid drinking Mountain Dew and eating potato chips all day while playing WarCraft is no more healthy than the 6'0" 220lb guy who lifts bricks all day doing construction. But BMI would suggest differently.