It creates confusion as to the safety of GMOs (How often does the federal government require labeling for something that is not harmful in some way?)
It's not necessary as the prevalence of GM corn and soy has pretty much made it that unlesss the item is "organic" it has GMO's in it.
GM food has become virtually impossible to find in Europe due to labeling the stigma wrongly attached to it. This would have a devastating effect on farmers who would see a drastic decrease in crops (and thus incomes) if they went back to non-GM crops. Plus they'd be far more vulnerable to droughts and water restrictions like currently in California.
And most importantly, It's allowing unfounded fear to dictate science.
It doesn't create confusion to safety. It informs people that the food is genetically modified. If the individual cares, they can do research like you and me. Lays is required to label their potato chip ingredients which are oil, salt, potato so the federal gov't requires labeling for tons of things that aren't harmful.
One can play the semantics game that it's not the actual food that people take issue with all they want. The reality is, a very large portion of GMO foods are modified to withstand systemic chemicals made by companies like Monsanto. Someone here said something to the effect of "just wash your food" or some nonsense before and that just illustrates the lack of knowledge when it comes to the byproducts of using GMO products and why it's disingenuous at best to look at the food, isolated in a vacuum. "It's not the food that is bad for you, it's the chemicals in them that you should take issue with" is pretty silly in this particular context.