The American public is, shall we say, less than perfectly informed about matters of politics and policy. For instance, people believe that foreign aid makes up a huge portion of the federal budget, when in truth it accounts for less than 1 percent of federal spending. Indeed, if voters were all well-informed, you'd barely need campaigns at all, since people who pay lots of attention to politics and understand issues are almost impervious to the persuasive efforts of 30-second ads and inflammatory mailers.
But every once in a while, the public will actually figure something out on their own and come to an accurate conclusion about a policy.