If we can consciously shuck this counterproductive flailing against integration, maybe we can actually get somewhere.
Japanese social groups are extremely exclusive- on the broadest level, foreigners are excluded from some establishments, banking and housing services are sometimes inaccessible to foreigners. And on a smaller level, there are also establishments that do not accept new customers without an introduction, local or not. Such exclusions are an integral part of the culture - the language itself is a shibboleth, you know your place and standing in the world by the language other people use when they speak to you.
Even more so because many Western countries are at high risk of being in Japan's position within the next 20–30 years.
Japan reached peak population growth roughly five years ago. Japan was informally understood to be an ageing population before that but now they are statistically formally so.
Hence the West would do well to watch and learn from how Japan prepared and how Japan continues to manage an ageing population.