As has been said, it's not just the Americans - you could definitely ask the same question of the English. And the answer in that case probably would be, no, most English people are astonished to find out that lots and lots of people genuinely feel dislike what what they see as Englishness. And I suspect Americans feel the same sort of surprise when they come up against it.

This is a completely different question from whether there's any rationale for the dislike. It's about the way bigger/richer countries tend to be more parochial about things than little country. The news world tends to stop at the borders. "Birmingham man killed in Earthquake", that kind of thing.

People in little countries (I mean the ones which are linked into the big world by modern communications) can't be so isolated from what goes on, including how people feel about them. And of course the sense that rich powerful people don't know anything about the things that matter to you is another factor in annoying people.

But the real thing to watch out for isn't the people who dislike the way they think you are (whether you're American or Irish), but the people who admire you for things that you aren't too proud of yourself. You used to find people admiring the English for building an Empire, and you still find people admiring the Americans for the same kind of reason. Nasty little people who like the idea of being able to push people around. You don't find them admiring Woody Guthrie and Pete Seeger and Garrison Keeler and Leadbelly... And they don't like Morris Dancers much either. They liked Maggie Thatcher.