The changing of a phone number isn't going to increase the number of suicidal people, so that 42% increase is people who would otherwise not have called, not people who would otherwise not have been suicidal.

Well, part of it is just the lighthearted ribbing that most culturally similar countries give to each other. Some of it is criticism of their godawful healthcare system and workers rights. Some of it is a criticism of their foreign policy, read imperialism, although that is arguably not as bad as in other countries that have actively invaded places.

Then there are the stereotypes; such as excessive national pride in a low average country, that could so easily do so much better.

There are countless other things also, but how many of them are America specific is debatable. It would probably be easier to ask people individually what their opinions are, as they are likely varied. Do those expressing this sentiment not inherently state their issues? Why not ask them directly?