Why does my future mother in law hate Turkish people?

I'm engaged and my fiancee is Greek - American. Yes, it's like that movie. Luckily they like me, mostly, it's been a challenge. But that's not the question. My future in laws have been trying to rent out a garage apartment. My fiance and I have been doing the interviewing. As it is near the beach we have had mostly groups of young guys applying and it's obvious that they are only interested in partying and are going to raise hell. A nice young couple applied, the wife is pregnant, the husband has a good, stable job and they are the obvious choice. However, when my future mother in law saw their last name she just about had a cow. She called them stuff in Greek that my fiancee said translated to barbarians or cavemen. She would rather rent to a gang of party boys. I don't get it.