Why do so many Americans suck at geography? I had to learn all the countries and their capitals in school. Granted, I don't remember all of them, but I know where Nicaragua is.
In the US geographical education is tightly linked with civics and history education... both of which have, for decades, been infected by layers upon layers of intense politicization. Due to the high risk of invoking controversy the solution to the problem has often been to water down the subjects or simply not teach them at all.