Kysha,
I haven't read the stories yet here but I just want to tell you that I understand how you feel. I'm biracial (Asian/Caucasian) and not being identified as part of the dominant culture I frequently find yourselves in situations where I get blindsided by blatant racism from unexpected sources and don't even realize I've been marginalized until its a second too late to say anything. Or worse, I just keep it in because I don't want to make someone else feel uncomfortable. Then I just stew about it until it goes away. Like a friend talking about how we can't meet with our kids at a certain park "because the Third World likes to congregate there".
And then there are times (infrequent ones) when I overreact to something that was completely benign but got my dander up for some reason. Embarrassing for everyone.
I can totally see reading something like that and not really knowing how to react. And if it made my kids uncomfortable I'd be doubly confused. I hope you found a resolution. I think the important thing is that you didn't have a knee-jerk reaction. You really wanted to consider it from all perspectives and the more everyone does that the better for everyone.