If I feel uncomfortabel standing there, I would either leave or say somthing, like: Not all Chinese are like what you just said, you can see people are being rude everywhere, every places, it doesn't has anything to do with their nationalities or races. What I mean is this white old man was being rude himself, he used bad language, right? he shouldn't use one unpleasant experience to attack all chinese, I think he is either a racist or having prejudice againt chinese. If I were you I would rather say something, He made you feel uncomfortable, and you didn't offend him, right? That's not right , what he said is an offence to all chinese.