[JoeB]

I disagree. The appellation 'Jap' is considered derogatory and insulting in American usage, especially by Americans of Japanese descent.

It might be said it's all in the eye/ear of the beholder, but that's just as true of any other word which is considered a racial/ethnic slur, and similarly if American or British English speakers claim that a particular word is not sensitive in their version of the language, so they needn't concern themselves about it: they are unlikely to feel that way when the shoe is on the other foot.

It's a historical term when used in original quotations from the WWII era and should not be censored out in such cases if the quote has overall historical value, but if those captions were written recently, then I agree with Dénes.

Joe