I'm pro GMO, in general. It's ruined the flavor of my food and moncultures are setting us up for failure. Neither of these things are the actual fault of GMO, but just people being greedy and and shortsighted.
I think why GMO gets such a bad wrap is pretty much why other myths can take hold in liberals: Their distrust of corporations and their vivid imagination. I purposely singled out liberals, as they seem to be the biggest proponents of anti-GMO legislation and labeling, and because I see parallels between that and the two other major things liberals tend to believe even though science doesn't back them up (ie Nuclear power should be banned, and the a lesser extent the cross-political antivaxxer myths). If you look at these myths what is underlying them is a fear of corporations (Monsanto wants to turn us into zombies/The corporations running nuclear power plants don't care about our safety/Big Pharma wants us to stay sick) and then an overblown sense of doom that stems from those feelings.