My grandmother-in-law saw both of her parents die in the Firebombings of Tokyo and eventually moved to the US as a Japanese War Bride (also sometimes considered an offensive term, many prefer to be called international brides). She endured several unfortunate instances of being called a Jap in a most hateful way. So, yes, it is a very loaded word that one must be careful with.
That being said, let's all be civil to each other! Let's not let the anonymity of the internet release our inner id's.