I think the answer is they are more afraid of something that might happen in the future than they are of the immediate and more definable consequences of their decisions in the present. For the most part, those making these decisions are not eking out an existence and their decisions, which affect millions of hungry people living on the edge of subsistence, and driven by their anxiety of some future events, politics, and self interest. Is it really a decision that is in the best interest of those who are most vulnerable? Would they make the same decision if they and their families were hungry?
What should be their priorities? I should not totally discount their anxieties about the future. However, weighing the present vs. the future should always be examined through the lens of the magnitude of present problems, the likelihood that immediate action with provide relief, how likely unintended consequences from the action might be, and the likelihood that other trends outside of human control will dwarf any human driven effects. In the case of GM modified crops, the recent track record is consistent. Where they have been deployed, their effects on the human condition are positive. Food is more abundant and cheaper. I see this in nothing but a positive light.
How likely are catastrophic consequences? No one knows, not even within orders of magnitude. However, mankind has been manipulating animals and crops for thousands of years. As man moves into areas and exploits the environments, they evolve. We carry both GM and non-GM entities into places where they did not exists before. This included kudzu into the South, lampreys and tiger mussels into the Great Lakes, wild pigs into North America to name but a few. Yes, the world was altered. No, it did not come to an end. This all happens on a long term background of continents moving, climate changing, and occasional asteroid impacts.
I look at this scenario and I see similar themes in the delivery of health care. We are faced with the health needs of patients and have limited resources to deploy to address those needs. Like the hungry people of Africa who have immediate needs, we have no shortage of people who are suffering directly from the effects of illness. They are in pain, are short of breath, have limited mobility, are depressed, or are limited in some way by their illness in the here and now.
At the micro level, the same scenarios play out when patients and physicians interact. My own experience as a physician is that we often are not able to distinguish our personal goals and fears from the actual patient goals and fears. We avoid taking personal risks, even when it means we become ineffective at addressing immediate suffering of patients. We discount patient fears when they are not our own fears. We fail to acknowledge that some of our own fears are irrational and patients should discount them. We end up depriving needy patients of interventions that can effectively deal with their immediate needs because of our own fears (often irrational) and our own self interest disguised at best as paternalistic protection of the world in general.