they don't import immigrants from third world countries
They do though.
They pay billions and billions of yen to import bottom barrel people from a failed state.
They put these immigrants in useless things called "United States Military Bases" and then spend billions of yen more trying to stop these thugs from killing and raping locals.
I once heard someone claim that Japanese trains were more on time than British trains because "the Japanese didn't erase their culture with immigrants" still don't fully understand how immigrants are making the train late.