perfectly acceptable

At least some governments in Japan appear to disagree:

https://jobsinjapan.com/living-in-japan-guide/housing-discrimination-challenges-faced-by-foreigners-in-japan/

Japan signed the “International Convention on the Elimination of All Forms of Racial Discrimination (ICERD)” in 1996

Tokyo Metropolitan Government educates real estate agents on the illegality of nationality-based rental refusals, considering them discriminatory

And the article itself seems to contradict with those statements...