I certainly didn’t know all these specific facts, but I did know that migrant agricultural farmers continue to be exploited. My point is, however, that even if somebody is aware about this fact, and deeply concerned about it, that won’t stop them from using the phrase “cotton picking“ if they are not consciously aware of the fact that it refers to picking cotton. I was not aware of that, just as I was not aware that pipe cleaners were designed for cleaning pipes. That’s why I’m inclined to give that teacher a break, if they are willing to learn from their mistake.