Probably the biggest reason why is because GMOs -- genetically modified organisms -- in general were not created by food or agriculture companies. They were created by Monsanto -- the same biotech and chemical company that brought us DDT, PCBs and Agent Orange. Monsanto also marketed aspartame and created bovine growth hormone (rBGH) to infect milking cows that put pus into commercial milk.
That's what the big deal is.
Sources:
http://www.panna.org
http://www.naturalnews.com
http://www.naturalnews.com/037245_GMOs_labeling_GM_crops.html
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