Well, in fairness I think every country focuses on their own history and culture for the most part. I mean even with the Roman Empire, we mostly learnt about Roman Britain and not the the empire as a whole. So whilst it is 2000 years ago, it is still the history of our country.
I think almost all school studies will have a major focus on the culture its coming from. But the difference is, whilst we did mostly study things related to the UK, America has such a huge cultural dominance that it was inevitable it would slip in. If you study the economic struggle of the 30s, you have to start with the Wall Street Crash and the American economic policies that led to it. If you study commercialisation in Geography, then most of the huge companies dominating the world are American. You study literature, so many of the ‘classic’ texts that schools want to teach are American that some kind of study of American culture is inevitable.
In my school you only had to study history until you were 14, and after that it was optional if you wanted to take the GCSE and A-Level, which I did. Before that, when it was compulsory, it was almost all British history through the years, I mean starting with the Romans and moving forward to WW2. But once I got to the optional stuff it was entirely 20th Century studies - and it was almost all American. We studied the Korean War, the Vietnam War, a thrilling unit called ‘American Economic Policy 1914-1945′… even when we did our unit on Germany 1918-1945, America was there. Because whilst it was essentially a unit on WW2 from the German perspective, America had such a huge role in the war that it couldn’t be ignored.
We all focus on our own countries and cultures. Its probably just a lot easier for Americans to learn by focusing only on their country. Because its their country that has been the worlds largest superpower for over a century.