From the perspective of a physician working in a country with socialised healthcare:
Fat people deserve to be brought to light, publicly condemned, and rehabilitated. They're addicts who continue to indulge in their favourite drug. And I don't know where you are from, but here the costs of treating the complications of being fat, comes out of the taxpayers money. And heart attacks are really expensive to treat. Quadruple bypasses are too. For those who end up with diabetes, the cost of complications is enormous. Don't just think of a little insulin, but a generation of people with amputations, kidney failure and blindness.
At least smokers pay for their treatment indirectly with high taxes.
In the interest of public healthcare, being fat should be just as politically incorrect as smoking crack. Problem is, there's too many of them, and they vote, and buy things, so that change will probably come in a generation or so, when they become unsubstantially expensive to treat.