I can understand that people are personally upset when they are affected by travel restrictions, but this whole outrage about "foreigners are second class citizens" (often even: "this shows Japans racism") is just just silly.

1- The restrictions are not about race, but about which countries have mismanaged the pandemic. People from Taiwan and some other south east asian countries are allowed to enter. (Ironically, exactly those people are / have been much more commonly the target of Japanese racism).

2- They most likely would prefer to also ban Japanese citizens (whatever race) from returning from hot-spots like Florida or Brazil. They just can't because of legal reasons. Citizenship gives you certain rights.

3- You can call PR and other visas "second class citizenship" if you want, but the fact is: you're just not a citizen. You also can't vote. You also can't become prime minister. You're not a citizen and don't have the rights of a citizen. That's the same in every country, including yours. Why didn't people with PR complain about being "second class citizens" for years about those other rights?