> via a Gulf style guestworker program

They get to keep their passports and can return any time, calling it Gulf-style is a bit much. There are abuses - so are there in Europe - but it's not like they sacrificed a thousand or so immigrant worker lives on the Tokyo Olympics in Qatar 2022 style.

I think they mean gulf style as seen by westerners. You can get a visa but you'll never be seen as a "local" nor granted citizenship. In places like Dubai multiple generations live without ever getting citizenship or a path to it and always with the notion you can be booted at any minute if you inconvenient the wrong person or run out of money.

Though I don't think this is fully true of Japan -- it's one of the easiest countries to naturalize in if you give up your other citizenships but does have the quality of always being seen as a foreigner. It's just that few people naturalize as Japanese because their immigration is most open to people from developed countries who aren't interested in giving up their birth passport to acquire Japanese nationality. If you just want a Japanese passport though no matter the downsides, I think it's one of the easier citizenship to get for an American to obtain.

    > it's one of the easiest countries to naturalize

This is no longer true. With recent legislation, you need to live in Japan for 10 years before applying for citizenship. In the old days, it was only 5 years, which is pretty short for a highly developed nation. UK, Canada, Australia, and New Zealand are now much easier to obtain.