It's hard to believe how touchy people are. Will people really take increased serving sizes as a signal to eat more? Probably not. It won't change anything for those who don't pay attention to calories/serving sizes nutrition. People who count calories will shit a brick and hopefully start eating less processed foods.
This is all really pointless anyways. If the FDA really wanted to address obesity they need to take a hard stance against processed foods and high fructose corn syrup. That will never happen because food companies will lobby to protect their empires and a large portion of Americans can't afford to eat real food.