Whether Europe or North America have a problem with too much immigration and not enough integration is debatable, maybe - and I suspect that's where your perspective comes from - but Japan decidedly does not (maybe too much tourism, and I feel at least some of the antagonism towards foreigners comes from that, but no matter). Immigrants still make up a very small percentage of the population, mostly in Tokyo; given the existing challenges with immigration, they tend to be extremely diligent, respectful, appreciative of Japanese culture, and hard-working.
This is just a populist conservative government pandering to the some of the worst aspects in society to distract from their failures.