Some of these kinds of nationality/noun things ARE intended as pejoratives. Most seem not to be, however.
I think that "Japanese tourist" is a slight slam. I believe it has to do with going places dressed fairly wildly for the venue, carrying two or three cameras and taking shots of everything. Like I did last week at my granddaughter's wedding.
Didn't they used to call American tourists "the ugly American"? Sure they did.
I am originally from California, and am reminded of something called a "Chinese Fire Drill" or sometimes "Mexican Fire Drill", where a car full of young people stop at a red traffic light and everyone exits the car and re-enters it using a different door from the one they exited at, frequently including the driver. This is amusing to watch, and probably a scream to do. It works only on 4-door cars, though. It is possibly offensive to Chinese or Mexican people, and surely not PC, but I doubt it is intended as a great insult. Best to give it a different name, I am sure.
Then there's a Dutch Date, which is where a man and woman go on a "date" and instead of the man paying for everything, they each pay half, or for their own expenses. Dutch refers to Holland, or the Netherlands, of course. This has to do with thriftiness, I suppose and I don't know if any Nederlanders would be offended by the term.
And how about someone who is counted thrifty being referred to as being Scotch? Which is a misnomer, since it should be Scot, or Scottish. The legend being that Scots are very thrifty. My own Mom used to say of my father spending money on something she didn't approve of, "That just gets my Scotch blood all riled up!" Any Scots offended by this?
And let's not forget "That's White of you!" This is an oldy; it is meant to imply approval for some favor. A variant when supplicating another for a favor was "Oh, be a White guy and [do this thing for me]." The last time I heard it was in 1968 in high school in Toronto, Canada when a friend and fraternity brother of mine used the former phrase to commend another one our fraternity brothers for something he had done.
Ironically, the particular frat brother he was addressing was Colored -- you know, the old Apartheid term for someone who was part white and part black -- and this is appropo to mention because he was in fact from South Africa. Now THAT was very offensive, something the frat bro in question didn't seem to realize, but I did, and I cringed like a sonuvagun. The frat bro on the receiving end of this was, fortunately, a very laid-back and patient man, so there was no contretemps, but I was horribly embarrassed.
The first written records of an outbreak of syphilis in Europe occurred in 1494 or 1495 in Naples, Italy, during a French invasion. Due to its being spread by returning French troops, it was initially known as the "French disease." Ouch!
I can't think of anything else at the moment. Fortunately.