Well, it's always been annoying for Canadians, I can tell you that. Harmful? No, it shows considerable narcissism, which ain't incorrect; so let's say it's more of a valid indicator giving foreigners a bit of a heads up about what they'll be dealing with than a harm.

This feels like an odd angle to take. The goal of such a list is to enumerate things that people might not realize are imprecise. Nobody needs a printed list to tell them the impact of titling their email "You little shit". But plenty of people have been saying "America" to mean "United States" for a long time without thinking about it.

We've always enjoyed the general inability of the average central north american to name a country that starts with the letter 'U'.

[1] https://www.youtube.com/watch?v=SQVe_cv2NMo