I think that one of those observations you're not supposed to make, or at least say out loud.
They allow very little immigration and only a few guest workers. They have a fair number of Filipinos who work in old folks homes. I'm no expert on Japan though. I just watch Japanese news pretty often and have heard about Japan from coworkers.
I believe their societal uniformity reduces violence in their culture and it is usually the mentally ill who create most of the violence. Unity is strength, not diversity.
“They allow very little immigration and only a few guest workers.”
A while back they had some problems with a few Iranians in Japan. They rounded every single one of them up and expelled them.
L