Earlier quoted context omitted.
>I know immigrants have nothing of value to offer to the Japanese people. I don't know how that makes sense. People can't offer people anything outside of some described cultural boundaries?
Having seen how Japanese work I know that the work ethic, reliability and efficiency can not be matched by anybody else on the globe. Foreigners would drag down the average which mathematically means nothing else than effectively extracting resources from the host society. The exchange of ideas can always happen via tourism, Internet, business or whatever. Multiculturalism has nothing to do with the exchange of ideas…
You talk about tribalism and war, that's a choice someone makes, and that's on those who choose it.