The Arrogant American became the Arrogant German (1990s / 2000s), and is now often the Irate Brexiter.
Being identifiable (appearance, langauge), significant in number, and crossing some threshold of observably obnoxious behaviour tends to leave impressions.
Within the US, you'll often find neighbouring-state stereotypes: "massholes", Texans (particularly in Colorado), Californians (Oregon), New Yorkers (city, everywhere), Yankees (the South), Southerners (the North), city slickers (country), country hicks (cities).
Much of this is inherent tribalism and not matching local patterns of speech, behavioiur, specific local knowledge, and the like.
Being identifiable (appearance, langauge), significant in number, and crossing some threshold of observably obnoxious behaviour tends to leave impressions.
Within the US, you'll often find neighbouring-state stereotypes: "massholes", Texans (particularly in Colorado), Californians (Oregon), New Yorkers (city, everywhere), Yankees (the South), Southerners (the North), city slickers (country), country hicks (cities).
Much of this is inherent tribalism and not matching local patterns of speech, behavioiur, specific local knowledge, and the like.