“棒子” is a new term to me and I don't know what it means.
I worked in LA twenty years ago for two years, and there was a very large Asian community. As being young, I didn't know better, I like to ask Asians I meet there "Are you Chinese?". If he/she is a Japanese, he would smile and said he was not. And to the Koreans, you could immediately sense some displeasure coming back toward you. Since then, I never asked the question again.
Then at the same time, a Chinese colleague of mine from Singapore was dating a Korean girl and they decided to get married. The girl's parents never showed up at the marriage ceremony (and as I understood then, talked to her again), just a bunch of us colleagues there.
I am not saying all Koreans are racist, but we have to be sensitive.