...Education??Discrimination??

I don't understand quite well the education of some kind of..people here...
I'll put an example: Today.
I'm from spain but I've got a german friend. Today we went to an amusement park, we were waiting in the queue, talking in german. Two girls were behind us, hearing us. One of them said: Let's insult them, since they're foregeins, they won't understand us. They started: stupid, bitchs ... (in spanish)
I turned round and said: Hey you, You know, I'm from spain and I can understand you perfectly,
-So? she said, she was embarrassed and said nothing.
I think it's really a shame. Those girls being raccist at a very young age...
Well bye..