The problem is not allowing or disallowing GM food, but the strict labeling requirements in the EU. If there's GM involved it must be labeled accordingly. Unrelated to if oppposing GM food is a "knee-jerk" reaction or not, the labeling requirement is a good thing, as it gives the consumer the choice which type of food he prefers. The trade agreement would weaken those labeling requirements, which is the main source for concerns here.