Interesting...without being there, it's hard to know.

I know from experience in Japan it can cut both ways. Sometimes, my colleagues and I got the best table and best service at the local yakitori joint - that happened after several years of twice-weekly attendance, working our way up the "seniority" list, so that ultimately we became one of the older-time groups and therefore, according to their concepts, worthy of the primo locations. In that case it didn't matter we were gaijins, we just had to serve our time and buy our beers.

But then again, I've entered another izakaya and the salaryman on the barstool looked me over his sake, and then turned to his friends with a casual

gaijin...dakara baka ni shite iru. kampai!

Quite insulting...to which I said, so desu ne... ano nihonjin bakano to iu hito atama ga inai desu.... that dealt with him.

Anyway, traveling with Shark Jr we've also been denied seating at an empty restaurant in Kamakura, provoking a reaction from SIL similar to the OPs. OTOH we brought Shark Jr back to our old izakaya to a very warm reception.

Working with several world-renowned researchers who lived in Japan for decades and wrote books on this topic - books that are used as texts for university sociology and anthropology classes worldwide - it's clear you can't escape from nihonjinron ideology and it always manifests in these ways.