None of these posters are "far leftist." As religious people, they believe they are to eat what G_d gave us, that we are not to tamper with His creation as they understand it, pretending to be creators ourselves. At worst, they see it as blasphemous mockery.
Little do they know what Genesis actually says in the Hebrew. If they did know, they'd be shocked and ashamed, and possibly go into depression for the way they have been deluded. Yet in fact, they had never studied the Word itself, but its human facsimile in translation, long distorted from a mistaken understanding through a mystical priestly lens.
This is a Book written by shepherds, not priests. Frankly, I don't think they know G_d as the shepherd does, or hear Him the way they heard Him speak. They need to get out a little more often.
Unfortunately, that lifelong "understanding" led them to discount the intent in the user of a technology, declaring the technology itself to be the evil. Yet they know very well that one doesn't blame the gun for the crime but the user. True it is (at least in my opinion) that what Monsanto is doing with recombinant technology is despicable, for which to my mind the members of the board should be jailed. Yet that is more for engineering a deliberate theft from the American people that enriched them (patent manipulation) and racketeering market access through the USDA. Little do these "true believers" understand that it is the regulatory architecture they wish to wield that is responsible for the motivations that abetted Monsanto's evil behavior. Little good and a lot of harm will come out of employing a tactic like Prop. 37.
Worse, it is that regulatory legal architecture that limits the array of weapons we can employ against pestilence, such that we use more of those few that are "permitted." This increases the likelihood that pests will develop resistance to these useful toxins and more of each must then be used (much to the delight of their producers), of which "RoundUp Ready" is a prime example. It is a fearful loop.
I do agree with you that it is shocking that they refuse to question the legion of Marxists in wholesale opposition to this technology as to what their usual misanthropic global corporatist agenda might be, but it isn't hard to see: export food production to countries with very little and VERY corrupt oversight systems with little to no domestic alternatives besides themselves. All Monsanto had to do was to put money into "anti-Prop. 37" advertising and they were all for it. "Oh please don't throw me into dat dare briar patch!" Strange bedfellows indeed.
If you haven't already, you might wish to check out my first book, Natural Process. It touched on Bt, and that was twelve years ago.