I manage to find this funny because I knew the exact same situation, was in the exact same situation, and even perpetually in the exact same situation with my own parents.
It's not really 'racism' or anti-anything.
Well, actually it kinda is, PC wise, since it involves the idea that marrying an outsider will corrupt their son/daughter because of what race/religion/culture he's from. or adheres to.
It's called endogamy, and it's popular anytime you have a minority immigrant population. I seriously cannot count the number of times my parents have said they want to go back to the home country and find me a nice Bengali girl to marry. And after I tell them 'no deal' they pretty much make it clear that they'll only accept a Muslim girl if she's to not be Bengali.
Suffice to say, I got double treatment of the angry minority parent from BOTH sides of the fence - from many a girlfriend's traditionalist parents to my own parents angry for dating a non-Muslim/Bengali girl, and secondly for dating at all. I keep on telling them 'but she's a nice Jewish girl, that's not so bad yeah?"
Oh, and I'm not allowed to marry American Blacks or Whites. They're pretty adamant about that, lol.
My dad, trying to be as diplomatic as possible in his answer (he knows how modernized I am), sums it up as, "their culture is too different from ours and you'll have problems in marriage."
It basically means that me and my non Muslim/Bengali wife will have lots of trouble with the in-laws who usually don't understand, yeah?