There is a very important disctinction.
It is one thing if someone uses words which are merely insulting (like Jap) or if you are fat, Fatty, or if you are ugly, 'Spanner', or if you have a big nose...'concord'.
It is quite another thing, to discriminate against people in terms of jobs, or to do violence to them becasuse they happen to be Japanese, or are fat or ugly or have big noses.
The practicality of the situation is that people tend to get discriminated against for one of three reasons: they are not of the indinginous population (in our case, white), they are female, or they are disabled. It is a bit arbitary, but be happy that you at least have that muc on your side.
In all three cases (sorry Lasz, including women) people of these groups represent significant population sectors, and have an equal mental ability, but haven't been given the breaks. Like blacks until the the Tuskegee (sp?) airmen.
So my view is that if someone happens to call you a jap (or me a Paki) deal with it. It's really not a big deal.
As Lasz said, it's a question of intent. Most people can detect malice from just a word that's used in passing conversation.
Seems to me you want to live in some sort of perfect world. Well, it isn't. So you have to learn how to take a few knocks and grow a thicker skin. Particularly if the terms used only hurt your feelings.
Still, I salute your courage for fighting the point.
Ravs