That's not saying much. Most of us don't understand most science behind anything outside of our limited specializations. These beliefs are manifestations of people's distrust of large institutions.
People believe GMO is bad because they believe that large corporations would do anything for a buck regardless of long term consequences.
Alien abduction, anti-vaxers, 9/11 inside job and other conspiracy theories are just ways for people to express their distrust of government.
Global warming deniers don't trust the liberal media.
The pattern is: I don't trust X. What is the worst thing I could believe about X.
There's a world of difference between a proper conspiracy and thinking GMOs and powerful pesticides might not be a good idea. I don't avoid them but I don't think it's all that unlikely they'll turn out to have negative effects.
People believe GMO is bad because they believe that large corporations would do anything for a buck regardless of long term consequences.
Alien abduction, anti-vaxers, 9/11 inside job and other conspiracy theories are just ways for people to express their distrust of government.
Global warming deniers don't trust the liberal media.
The pattern is: I don't trust X. What is the worst thing I could believe about X.