First of all, we don't know how the question was asked. And the way it is asked, can chage A LOT. I've seen some interviews of people in the streets (either in USA or Europe), and people are making dumb mistakes. But, you know, interviewed people are stressed, intimidated by the interviewer, camera or else. The question could asked very fast, and people can be too shy to aks to repeat the question - thinking that would make them idiot. If it is asked on internet or on a paper, one have more time to think.
Second, sometimes people does mistake. But is it representative?
Here was a map of France according to CNN...
But it is the mistake of only one or two guys, and doesn't make it representative of a whole population. I mean... In that link:
http://bigbrowser.blog.lemonde.fr/files/2013/10/CNN-21.jpg I want to see the stat! Is it significant? How population sampled? Are they middle aged people? Are they students? Are they jobless people, poor, rich, educated, non educated, white, black, women, men, are they from the whole USA, or west cost, south, north? And the same for Europe? What Europe?
Ok, right, it is interesting, and quite funny, but it is a bit cheap news to me. I'm from Europe, but I leaved in North America for a while, and I would definitely not say north american people are dumb.