I think it's time to ask - why do you support GMO labeling? If it really is an abstract "right to know," then why is knowing this fact more important than any other minutia?
Why, for instance, does GMO labeling stand out from all the other possible things we could cram on a package:
1) Grown in the USA (or not) as a percentage of ingredients
2) Average wage earned by the line workers/migrants for this food
3) Types of fertilizer used in ingredient production (animal waste, other)
4) Whether or not (and type) of pesticide used in the field
5) Percentage of product produced with non-union labor
6) Whether the product was cooked in any way during processing
7) Shipping method used - boat, truck, train...
8) The amount and type of radiation contained in the product (whether natural or derived)
9) The charities the producer contributes to
10) Any political donations made by anyone in the production chain
I'm sure there are plenty of other things someone, somewhere, would like to know. And, as much as my pig feces fertilizer label was discounted, I'm guessing your average Muslim or Jew might be interested in that information.
The reason not to label GMOs is simple: It creates an artificial class without merit. It's racism for food.