I would say that is a bit of an exagerration. I wouldn't say MOST Americans couldn't find the US on a map, and exporting such a "fact" for foreign public consumption only adds to the perception of the "ugly, pompous, uninformed American".
I won't disagree with the fact that many, and probably even "most" US citizens would have difficulty pointing out most Asian nations, many in Europe and the Middle East, and all of Africa. In addition, your assertion that the average American is uninformed about the underlying causes for the problems, strife, political make-up and history of all nations is certainly accurate.
It is frustrating to me as a fairly knowledgeable and informed citizen, not only of our history and politics but that of many nations across the world, that most Americans have a very remedial and inaccurate view of these areas. Further, so few people seem to even have a desire or interest to become educated in these matters. That is what is scary, IMO.