From hat i learned about Japanese culture it is not racism per se, think about how Japan in the past thought about Japanese people living in foreign lands, there offspring was not considerd Japanese, in the more extreme times anyone who left Japan to life somewhere else was automatic an foreigner.

I think it is more about a very strong idendification with the own culture, not in a malicious way, like racism is, one can consider the own culture all there is.

Japan is an isle nation and until a short time ago immigration was not an option (limited food ressources, limited area already occupied.

Not the breeding ground to be open to other cultures, so for the outsider it looks like an superior complex while the culture itself had to deal with limited resources, and how to prosper under this conditions, leading to very little interaction with foreign cultures, and if then they where violent.

Consider how often China tried to invade Japan over history, nothing that encourages to receive visitors with open arms or building a strong tourism industrie.

Compare to Europe for example, whole nations on the move all the time, trade from stoneage on from north africa up to north europe, people did rub all the time elbows with strangers not only during war times but in peacefull times too.

Beside brief times of nationalism there where always whole cities changing there place overnight, Kings interested in immigrants to import new industries invited whole populations.

North germany people from france for art and weaving, Russia people from england to gain people able to build good ships and do mining, the Swiss where all over the place as Mercenaries.

Compared to that Japan pretty much had only interaction with outsiders at swordpoint, it's closest neighbour was an country with strong armees and often in the mood to move it borders, outside.

Foreigners meant trouble.

So maybe more an cultural reflex, not racism.

(All that is what i think is the reason why things are the way they are, i am not formally educated in sociologie, i just like to read a lot)