I think their are two ways to look at this. People in the west sometimes expect everything to be the same as their home country when they go away. Its very important when you are in Japan or any Asian country for that matter to not go their with the intent that they should know you, and know where you are from. Have a big hello from the plane haha
The west is very individualistic. Japan is a nation where people are very together and working together, individualism is frowned upon to an extent. The togetherness and working together for good can be seen in how quickly they recovered after the March 11 earthquake and tsunami.
So they don't know where Ireland is, and you feel that you are looked upon unfavourably by the Japanese, or that they are racist. I don't think that at all. I think you will be given opportunities to show that you respect the Japanese and their culture. And when you are respectful, you will be all the more favourable included. I guess it is the same for everything, just be respectful. (que too idealistic comments :-) )