One of the things working in Japan's favor is that Islam has not established a strong foothold, especially within government. It is not easy to obtain Japanese citizenship, unlike here where we just hand it out to anyone that fills the form out. Therefore, foreign born individuals don't have a lot of say on policy. So, Japan is nipping their immigration problem early on in the process unlike the West where it has established roots over time. The Japanese also have a very proud cultural identity they fiercely protect. In the US, people have different ideas about American identity. Hell, some people can't even identify the difference between a man and a woman much less what an American is.