What to say to idiots who think GMOs are a good idea

I had a conversation about GMO. The name of the numpty has been removed to protect the guilty:

Him "I think GM could potentially be a big boost in developing nations, however the marketing, patents, enforcement, business practices of Monsanto are diabolical and should be stopped."

Me "You have been misled about GM, they could destroy everything, and they help with nothing. They are purely for profit and ultimately control of the food supply."

Him "I said potentially, after all we have been modifying food and animals for millennia. I would point out I have not been misled, I have read papers from an informed and educated stance, not biased data that had been discredited but still repeated by pressure groups and tinfoil hat wearers on Facebook. They are being used for profiteering. In countries like this that face real food shortages every year, increased yields or increased resistance would bring real benefit. However, subsistence farmers cannot afford them."

Me "Oh yes you have been misled and you are showing your ignorance there, A LOT.

You’re right, Farmers have used selective breeding for ages to increase the robustness and output of their crops and to produce and encourage other desirable traits. But there are some pretty huge differences between the techniques they have traditionally used and the high-tech ones being implemented today on mega farms that produce GM corn, cotton, soy, and canola (the four crops largely converted to GM technology so far). Put it this way: If traditional selective breeding is like two people with two different sets of genes being paired up by a matchmaker who thinks they’ll have pretty, healthy kids together, then modern high-tech GM breeding is like Victor Frankenstein slicing ‘superior’ body parts out of fifteen different corpses and using them to sew together his powerful, yet frighteningly unpredictable, monster.

To make a GM plant, scientists need to isolate DNA from different organisms—bacteria, viruses, plants, and sometimes animals (or humans if the target gene is a human gene). They then recombine these genes biochemically in the lab to make a "gene construct," which can consist of DNA from five to fifteen different sources. This gene construct is cloned in bacteria to make lots of copies, which are then isolated. Next, the copies are shot into embryonic plant tissue (microprojectile bombardment), or moved into plant tissue via a particular bacterium (Agrobacterium) that acts as a vector. After getting the construct copies into the embryonic plant tissue, whole plants are regenerated. Only a few plants out of many hundreds will turn out to grow normally and exhibit the desired trait—such as herbicide resistance.

All in all, I don't want to ever eat that crap, and anyone who says someone is a dim witted tin foil hate wearer for not wanting to, is in fact a complete idiot themselves."