A lot of these groups specifically target Monsanto, a giant agricultural and biotechnology firm which has some shady history and legal issues, as well as being accused of "playing God" or population decline or something. It is the bogeyman of the anti-GM movement, and I'm sure the little children everywhere are frightened by the campfire stories of Monsanto and the cancer-giving corn.
The reality is, as always, much more complex. Monsanto surely does have some predatory corporate practices, but it is also, you know, a for-profit corporation. I won't pretend to understand the legal issues underscoring some of their patent claims, but I'm also not surprised - they have to make their money somehow, and losing control of their patented seeds probably isn't a good thing.
What they do not make money off, however, is trying to kill people. GM crops and foodstuffs are among the most widely studied products on the planet, and the science behind them is well researched and understood. We are not playing around with some new-fangled technology that was just recently discovered, and the issues surrounding the use of GMO seeds and their consumption are documented. The science is already in, and GMs are safe.
On the other hand, what isn't documented is the arguments from the anti-GM crowd. Their opposition comes mostly from ignorance of the science, and when they try to do studies to back their stories up, they turn out to be poorly-done mockeries of scientific inquiry. We're supposed to trust them because, oh, they're not in it for the money - yet meanwhile, they remain silent or cheer on while anti-GM personalities like Kevin Trudeau make millions by defrauding people; or when the "Health Ranger" Mike Adams uses legal trickery to silence critics; or while corporations use their opposition to GMOs as an advertising gimmick.
Plus, here's the other caveat never mentioned by the anti-GM crowd: how are you going to feed 7-billion people? GM crops are made to withstand circumstances would normally kill off harvests, they're modified to resist disease, insects, and weather. They've also been modified to provide more nutrition per unit, so as to reap greater efficiency from every crop yield and thus every product shipped to market.
In other words, they're modified to ensure people have better food security, and in a world with a rapidly increasing population, its a necessity. Yet the ignorant continue to cheer when fields containing GM crops are burned or protested against, with nary an alternative proposed.
Think about their position now - they oppose a scientifically-backed, well-documented and life-sustaining product on the basis of oooh its not natural! What utter nonsense - dangerous, ignorant, murderous nonsense.
GMOs are safe, end of, so shut up and eat your giant mutant strawberry already.