The Washington Post contains an article on a recent survey by Oklahoma State University where over 80 percent of Americans support “mandatory labels on foods containing DNA,”
The Oklahoma State survey result is probably an example of the intersection between scientific ignorance and political ignorance, both of which are widespread.The most obvious explanation for the data is that most of these people don’t really understand what DNA is, and don’t realize that it is contained in almost all food. When they read that a strange substance called “DNA” might be included in their food, they might suspect that this is some dangerous chemical inserted by greedy corporations for their own nefarious purposes.
The article discusses the wider issue of scientific ignorance driving policy decisions, and there is some further comment at io9. A summary of the full survey results is available (PDF).
It's not a matter of sucking, it's just that most people are easily confounded when asked about non-everyday terms, specially if the question is expressed with intent to get a visceral response.
There's a similar case from some years ago about asking people how would they react if their children told them that they were heterosexual. Few people stopped to fully understand what was the meaning of that before answering.