I am an English teacher, and sometimes hear my students using 'taboo' words, or even just slightly inappropriate words. I do not think it is my job to teach these words, but as the students will hear them when watching movies, I feel that I need to let them know which words are OK to use in general conversation, and which are impolite, or even very rude.
The reason I do this, when the need arises, is because some years ago, I was getting my hair cut, and my hairdresser who speaks only very little English, told one of the girls who works in his salon to 'f*** off". I could not explain to him why he should not speak to her like this, because his English is not good enough, but later, I got a friend whose English is better, to go with me, to explain to him the meaning, and the reason to not use this expression in the salon.
He was terribly embarrassed, and apologized to me a lot. He had heard the expression while watching movies, and had no idea of the meaning, or that it is not considered polite language.
So, although I do not actively teach these words in class, I do try to make take advantage of an opportunity to point out that not all English words they may hear, particularly when watching movies, are polite, or even appropriate to use in general conversation.