Why do Americans and European pundits think Japan is "anti-immigration"?

Landing immigrants at Castle Garden, NYC

It is true that Japan doesn't have promotional policies where they reach out to other countries and ask or encourage them to immigrate, but Japan does not set up laws with the intent of reducing the number of mid to long term foreigners. And sometimes they tweak new or existing immigration laws if they perceive them as being too hard to too lenient or they have loopholes which can be exploited.

Limited "family reunion" policy reduces "chain migration"

The primary difference between the U.S. (which has a high level of immigration) and Japan's immigration system is that the U.S. immigration policy allows for two major paths to legally immigrate:

1. By employment: getting a job that is considered immigration worthy.
2. By "family reunification": having a family member (brother, sister, mother, father etc) already in the country.

"other" includes "diversity" (green card lottery) candidates & refugees/asylum seekers

In America, at least 50% and up to 70% (depending on the year, since 1965, thanks to the Immigration Act of that year) of legal immigration comes from path #2.

Japan, on the other hand, generally has only has one major path:

1. By high skilled work. How this is defined is complicated, but in a nutshell it's anything that requires a formal education above high school level.

"other" includes refugees/asylum seekers; "designated activities/work" includes PR and SPR

Chain Migration compound effect

In Japan, you can bring your immediate family (your spouse and your direct non-adult children), but you can't generally bring your mother, father, brother, sister, etc. If they want to come, they usually need to qualify via path #1.

This reduces the affect of what's known as "chain migration". Chain migration is when the immigration of one person causes or sets up or enables the migration of many other people: either directly (because they're family) or indirectly (the community and friends that surrounded that person/family who immigrated).

Up to your living great grandparents to qualify

There is a path to a Status of Residence known as "long term resident" (定住者 {teijūsha}). In the particular case where you can prove a connection to a Japanese national via 戸籍 {koseki} (family register) within three (3) generations and you can get access to that document (meaning you have the family register holder's permission to obtain a copy) and the generation is still alive, then you can qualify for this SoR that is almost equivalent to Permanent Resident (永住者 {eijūsha}) status.

This status initially attracted — and continues to though in lesser numbers from the bubble heydays — many Japanese-Brazilians (descended from Japanese whose ancestors immigrated to Brazil in the early 1900s) in the late eighties and nineties, as well as Taiwanese, Chinese, and Koreans.

However, because it requires a 3-generation-or-less connection to a Japanese national and not another legal foreign resident, its ability to cause "chain migration" has been relatively limited.

It is possible to obtain "Spouse or Dependent" status (永住者の配偶者等 {eijūsha no haigūsha nado}) with unlimited right to live or work by being linked to a foreign resident with PR status, but if you're married to a someone who is not a Japanese national (natural born or naturalized) or a permanent resident you need a "Family Stay" status (家族滞在 {kazoku taizai}) which does not usually permit employment without special exception.

Physically difficult and expensive to "get one's foot in the door"

Because Japan is surrounded by seas and oceans with no land border neighbors, it is geographically very difficult for potential immigrants to enter illegally, and makes travel (airfare) expensive compared to land/car crossings. That also keeps the whole immigrant (legal & illegal) population low.

Language, language, language

Most importantly, the language of the land is Japanese... so in order to qualify for Path #1 (high skilled labor), you usually have to speak/read/write it from Day One for most available white collar jobs (that would fall under a designated work activity worthy of a visa) in Japan. Yes, there are IT jobs and other STEM (science, technology, engineering, and math) jobs where you can use English (and there's teaching English), as well as elite executive jobs and expat jobs like those in finance, but in the grand scheme of things when looking at percentages, this is a tiny portion of the available jobs out there in Japan for somebody fluent in Japanese.

This is a much higher barrier than other countries, where the availability of high-skilled jobs in "popular" first/second languages (usually meaning English in the 20th/21st century) is more plentiful.