So what country do ou think is more similar culturally to the US, then?

Or is your point just that America is Special and can't be compared to anyone?

Why don't you choose one that has approximately the same population and same population density -- that's why choosing an individual U.S. state might be a better choice because the U.S. is large and has a wide range of population densities.

The key point here is transmission of an infectious disease, so to get a proper comparison, you need to start with approximately the same probabilities of people infecting one another. That begins with proximity. Comparing the U.S. and Australia doesn't work because of that.