Like insisting Italians arent white for example or that the Netherlands don't exist.
I think my favourites are those that take notice of the weird things certain national groups do online - Like "[X] WAS SERBIAN" and "[person] come to Brazil". I like how unhinged they are. Once you see a Serb insist Elvis was serbian then you kinda get it.
Hobby spaces have a lot of these kinds of jokes. WH40K people writing like tech priests or orks, discoposting here, that kinda stuff.
wa wa wawa wa wawa waaa wa wa wawa wa wa wa wawa waaa
yee
(exasperated look)