My first part on trying to answer that is, you acknowledge the human/emotional side of it, and discuss it.
"What you don't get is large masses of people changing their minds." (from your other comment)
No but what does? Propaganda? Silence? Unfortunately both easily used by the "other" side. I think only honesty works and let people figure it out. If ultimately that means we will not proceed on GMO, a shame in my opinion, but so be it.
"I don't think that's actually available"
You might be right, ...
However, I do think there is a second thing we can use. Show people the difference between knowledge and belief. Between opinions based on feelings and opinions based on knowledge. A strong proxy for belief/feelings not knowing or discussing tradeoffs.
"sound just like those people who work for Monsanto - which has happened to me today on HN." (also other comment)
lol, don't we ;) . Luckily the "other" side usually grossly exaggerate their points.
But you are right, ultimately people still have their fears and just grab other fig leaves.