Pig-iggerant Murricans are a pretty soft target. There are about 5x as many US citizens as Britons, so you'd expect 5x as many who were pig-iggerant. As an ex-teacher (I gave it up about 30 years ago) I can assure you that there are plenty of pig-iggerant Britons too. And for arrogant stupidity (as distinct from plain stupidity) I'll back China against the US.
My wife (who is American) reckons (a) that her education in NY State wiped the floor with California (where she moved when she was 18) and that most education in the US (NY State or California) declined fairly smartly in the 60s and 70s.
Even so, a few stories:
Motel keeper in Gettysburg: "You speak our language really well."
Me: "Um, well, yes. England... English. There is a connexion."
MkiG: "But you're from abroad and everyone from abroad speaks different languages."
***
Motel keeper in Arizona who had a sister 'in England'. Turned out she meant 'New England' and didn't know there was a difference.
***
American tourist in Malta, of megalithic ruins at Hagar Qim: "Why don't they take better care of these ruins?"
Me: "They're over 5,000 years old; maybe over 13,000 years old"
AtiM: "Yes, but they're just letting them fall down."
***
American tourist in Stirling: "Why did they build the castle so near the airport?"
***
Then there was the girl at Santa Maria High School when I lived in Guadalupe, California, who was worried that Saddam Hussein was going to invade the USA. Overland. She reckoned it was quite a long way to Iraq: probably three days' drive.
Don't blame the kids. Blame the teachers, and the kids' parents. An example from Guadalupe High School. A friend asked the children in her class their star signs; asked them to compare the predictions in their horoscopes with what actually happened that day (with a view to pointing out that newspaper horoscopes are mindless drivel); and was accused of encouraging devil-worship.
Incidentally I live in France, about 400 miles north of the Mediterranean, and am about level with the southernmost part of Germany, so for me, Germany is well north-east.
Cheers,
R.