I don't know why homogeneity is a good thing and for the record I am AGAINST illegal immigration. This knd of 'homogeneity' breeds bizarre racism and I know first hand having lived in Asia only that in Korea it is worse. You have to differentiate between following the law and just being stupidly racist. I have several friends in Japan who have lived there for years, some of whom speak fluent Japanese and can function in society and they are still outsiders. I am not sure what angle you are coming from; are you a white supremecist?
What does being a white supremacist have to do with anything? Homogeneity=social cohesion, a healthy society needs something that bonds everyone together, of course there are some exceptions but different races cannot blend together as a societal block and share the same culture. This is how it's always been. Japan is such a cool and desiring place because it is homogeneous.
I am totally against multiculturalism, the reason we have different cultures, architecture, foods, is because we have been separate throughout history. I think we should preserve these things and allow different cultures to thrive in their own environments...let in a ton of filipinos,somalians,chinese, whoever, and japan is not Japan anymore. Britain or Italy let in tons of africans and arabs, then they are not Britain for Italy anymore..the rate of immigrants to the west replacing the native population is alarming, and not a net benefit in the least, in France you cannot even feel safe on a bus anymore. It starts slow and then before you know it you've lost your country. Japan has nothing to gain past short term economic benefit from letting in non-Japanese immigrants. I guess we'll have to disagree but I hope you now where I'm coming from.