First off there's nothing inherently dangerous or unnatural about genetic modification. Several people pointed out, correctly, that it's just a faster way to practice husbandry than traditional methods. There's nothing more unnatural than a seedless orange or a turkey that is too fat to fuck. But it's also reasonable for people to be concerned that this sort of rapid change might have unforeseen health consequences. Gimlet and ql noted dairy farmers use of bovine hormones, which studies indicate may have unexpected health effects.
Second, there's confusion over labeling and FDA regulation. The current (thanks, O!) FDA position is that it is generally misleading to label a product GMO-free, and that ignorant consumers are easily confused:
The FDA doesn't generally permit GMO labeling. Most people unhappy about the absence of labels want producers to be allowed to label, not be required to do so. ql referred to a similar battle fought in New York over bovine hormone labeling. Same argument--stupid consumers need to be protected from themselves, so must be left uninformed.
Most, if not all, cultivated food crops have been genetically modified. Data indicate that consumers do not have a good understanding that essentially all food crops have been genetically modified and that bioengineering technology is only one of a number of technologies used to genetically modify crops. Thus, while it is accurate to say that a bioengineered food was "genetically modified," it likely would be inaccurate to state that a food that had not been produced using biotechnology was "not genetically modified" without clearly providing a context so that the consumer can understand that the statement applies to bioengineering.
My (parenthetical) point yesterday was that many people prefer to avoid GMO products even if they do not have safety concerns, and these people would like to know what they're buying. GMO labeling is not solely about safety. And, in any case, you'd expect free market advocates to oppose this kind of restrictive policy (as several people remarked).
But I'm still irked that I've never seem a headline regarding climate. "A Global Race Against Time Threatened By Ignorance." "Echoing the Tobacco Wars, Energy Industry Impedes Climate Progress." Those you don't see.