In responding to surveys, many people don’t want to admit they are ignorant about the issues the pollster is asking about. Just as we guess on standardized tests, so many people cover up their ignorance by guessing on polls. In the process, they often rely on crude “information shortcuts.” For example, “Agrabah” sounds vaguely Arabic, and survey respondents could assume that the pollster is asking about bombing it because there are radical Islamist terrorists there. That train of thought might lead hawks to support bombing it and doves to oppose it (13% of Republicans and 36% of Democrats said they opposed bombing, rather than challenge the premise of the question, or express no opinion). Similarly, the “Metallic Metals Act” sounds like legislation intended to promote metal production, which most survey respondents apparently viewed as a good thing. As for DNA, if you don’t know what it is, it can easily sound like some sinister chemical that greedy corporations might insert into our food for their own nefarious purposes. Why else would the pollster ask us about it?
People who realize that there is no such nation as Agrabah, know that the Metallic Metals Act does not exist, and understand what DNA is, are unlikely to rely on such flimsy conjectures. But most Americans don’t have that level of knowledge.
UPDATE: It’s worth noting that some of those who said they oppose bombing Agrabah may have done so because they realize it is a fictional nation and thought that response was more defensible than “not sure” (the only other option given, other than support and opposition).