I can see your frustration Maciamo.
However, Japan isnt the only place that this happens.
In New Zealand, so many second or even third generation asians get the same looks of bewilderment.
More so the younger asians that have been born in New Zealand, or came at a young age. Of course their english is perfect, yet they will walk into a store and be spoken to veerrryyyyy sllloooowwwwwllllyyyyy, and for some strange reason, a lot louder than a usual spoken, inside voice.

On a daily basis they are asked how long they have been studying english for, and where are they from. "Im from New Zealand" "yes, yes, but where are you REALLY from" "New Zealand" "Where were you born though?" "I was born in New Zealand" "hahaha, but what are you?" "Im a New Zealander".

Sure people dont marvel over their knife and fork ability, or their ability to eat certain foods, but they are constantly being treated in this belittling manner, for looking like they dont belong.
Hmm maybe this has gone off on another tangent.

Anyway I was just trying to show that other countries have their funny little ways of dealing with a slightly different painted picture.