It's definitely true that it's hard to hate a group of people when you personally know and like some people who belong to that group, so governments should perhaps look to create opportunities for people of different groups to meet and talk. In Australia too, anti-immigrant sentiment seems to be rising as economic times toughen. Currently, the ire is aimed at illegal immigrants and "boat people", but if things get worse, virtually any ethnic-looking person could be fair game.
He was Chinese.
He looked at my green tea. I looked at his masala chai. We both smiled.
But not all cultural interactions involving tea are so harmonious. A TED talk by researcher Sheena Iyengar exposed quite glaringly the rigid cultural barriers around the way tea is consumed.
I'm not an advocate of cultural relativism. I think the Japanese in this example were just being pigheaded. I could think of similar situations where I personally disapprove of someone else's choice but wouldn't dream of interfering. For example, I don't think much of the practice of Westerners drinking wine at an Indian restaurant along with their meal (because Indian food is not consumed along with wine), but if that's the way they want it, so be it. He who pays the piper may call the tune.