The first few depictions of this pairing annoyed me in terms of how their personalities were handled, but as time rolls on I find myself being entertained by it more.
Not sure about "yank" or "Brit", but apparently the word jap wasn't always offensive, but became so during WW2 and so it's been considered an ethnic slur (like nigger) since then.
Not that I disagree with people being overly sensitive regarding political correctness recently, mind you, just that the word "jap" has been considered bad for decades now, so it's not really a new thing.
I'm American but Yank doesn't bother me a bit. Although our history is one of turning our enemies taunts into patriotic songs and drinking tunes into national anthem so... kek.
I mean, it is one of those things where we should just ignore rather than trying to keep tally on who offended who and where. The more people remind each other on backgrounds that wasn't even theirs, just associated with their faction (race, religion, organization, country) the more friction it starts and then you get to the point where everyone is so polarized that "all lives matter" is suddenly hate speech. I'm overreacting but I really am sick of how pervasive this political correctness deal is getting. And I mean, I am probably one of the most self-righteous people out there, I don't forget when someone does something to another and I love it when people get their revenge or everything is otherwise "equalized", but some things you just have to turn away from and let go to make the whole situation better.
See, there isn't anything inherently wrong with political correctness, but the problem is that it's gone so far in the other direction that it's become the very thing it was fighting against.