I agree that Ayumi has always been interested in western culture, particularly that of America. Even though she comes to the US on business-related purposes, she definitely enjoys it for her own pleasure as well (she has cited favorite stores in different US cities and has mentioned that most of her jeans are imported from western countries)

To clarify, the genre of R&B is a distinctly American sound, stemming from music created by African-Americans in this country. Though other countries have an interest in it and have helped in spreading the love for R&B (and infusing their own music with R&B), it would be more than fair to associate R&B with America and/or the West.