Nah, Tunisia's the one being triggered when being called Turkey, not the other way around. It's much worse for a turk to be called a greek as there's always been a kinda "rivalry" between them. That's the joke here. Calling a greek, a turk or a turk, a greek is the equivalent of telling Scots they're from England.
Greece and Turkey have more in common than you think. Throughout History, Greece and Turkey have been fighting quite a lot. Greece stayed a Ottoman Empire's region for a pretty long time. Those two truly hate each others, well, at least they have some issues. The joke here, is that Netherlands calls Turkey by one of his "ennemies" name and Turkey doesn't quite appreciate it. That's how I personally got it.
I dunno, it might be funnier for me as it's something I personally spotted. I have greek family and pals and there's been times when people confused them over turks (as they both kinda have that "mediterranean look") and they got really triggered about it.