I agree with you Kaleo. If the kid is morbidly obese and needs to lose weight for their health, then it's the parent who needs to make sure the kid eats right and exercises. Now, you can't always control what your kid eats - but if you're feeding them healthy food and making sure they exercise then there is no reason why they can't attain a healthier weight (even if they are sneaking snacks at school, friends houses, etc). This is assuming the cause of the obesity is overeating and a sedentary lifestyle and not some other medical condition.
If you starve your children, that's considered neglect. I don't see why stuffing your children to the point they are in serious danger, health-wise, should be any different. The main responsibility of a parent is to protect your children from danger. These days, the food we eat is dangerous, and parents should put quality of food over convenience in order to keep their child safe.
I'm sure everyone has witnessed at least one clueless mother in their life, brainlessly offering their INFANT child a baby bottle full of soda. It's people like these who need a serious intervention and some strict guidance to clean their acts up. If all else fails and the child is still in danger, then you lose your right to parent that child.
Nothing that causes harm to a child should be tolerated.