Nobody wants to charge you for living your life.

People just don't want to be charged for your multiple bypass surgery. By being overweight, you have a much higher chance of incurring a very expensive operation than they do... which means that on average you would cost the system far more to insure than they do... Ergo, they want you to pay a little more for insurance, so they don't have to on your account.

I'm fat, and I approve of this specifically because I don't want my bad habits to be subsidized by someone else. *shrug*

That said, I cannot approve of this if they use BMI, since they will be mis-labeling people ~25% (or more) of the time, including almost 100% of athletes and almost 100% of physically fit males, as well as nearly 100% of tall people...

But if they used waist-to-hips... then they would merely be charging more for people that cost more. That's insurance, and it seems fair to me.