I disagree. Ethnocentrism cum sentimental fondness for oneself are ubiquitous, and non-US versions are even more obnoxious. What makes the US variety irritating is its high visibly thanks to the popular media. In other countries, the official ethnocentrism usually takes the form of revering the state and officialdom, while the more silly popular versions live mainly in the folklore and are occasionally ridiculed by the learned classes.
Wojtek