I thought BMI was pretty debunked as a measure of health?
I'm 5'11" or so, and weigh approximately 180 pounds.
According to that website, I'm overweight with a BMI of 25.10.
I certainly don't look overweight, I definitely don't feel overweight, and if I picked up my exercise regime again, I'd be more likely to gain muscle weight than lose weight. And yet, my BMI would get worse.