Originally posted by Vudak
So it's one of those things that probably wouldn't be a problem being used in real life with the proper voice inflection making it clear that you're not using it in a derogatory way? Which of course text can't get across?
Not quite. Because of past usage (context) it is offensive word no matter in what context it is used today. It may take few generations more before it is acceptable again.
To understand that better you'd have to go back to 19th century when Asian people (mainly Chinese and Japanese) were brought in US as cheap labor to build railroads and work on the farms.
In the West white americans were blaming them for their economic misery and anti-asian movements started (using inferior race card) and from then on the things got worse.
War started in Europe, due to German-Japanese alignment, curfew was imposed on all Japanese-Americans, they were banned from universities (so they couldn't learn German and spy for them) and after Pearl Harbor they ended in internment camps.
The quote by famous war correspondent Ernie Pyle describes American sentiment very accurately:
"In Europe, we felt that our enemies, horrible and deadly as they were, were still people, but out here, I soon gathered that the Japanese were looked upon as something subhuman and repulsive; the way some people feel about cockroaches and mice."
And the abbreviated term was used through the period by us to project that sentiment.
PS
Above text should be seen in historical context only.