system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do some developed nations (UK, France, Germany, etc) have large populations of migrants, but other developed nations (e.g. Japan) have very little?
gpt
Doesn't Japan have stricter laws about immigration and naturalization?

I would be surprised if there wasn't an illegal underground market for undocumented workers, however, like in Qatar, or UAE, or Saudi Arabia, you are treated like dirt and expelled after your work visa expires.