I'm not saying this didn't happen. But as an American myself, I find this bizarre. I was born and raised in Texas, and I can't recall ever meeting someone who didn't know what England is. Though I guess if you are visiting from England, the topic is more likely to come up.
I'm also convinced that every country has absolute morons within their populations. Our American morons are just louder than most.
I kinda envy them if so. To be so oblivious or isolated to not see the country crumbling around us....