Taboo language may change over time.
Example
Some learners in the Middle East regard the subject of same sex relationships as a taboo subject.
In the classroom
Taboo subjects, if carefully handled, can be a useful way to stimulate a response from learners, e.g. in a discussion lesson. It may be important to discuss taboos if learners are studying in a country where they need to understand the target culture.
Further links:
https://www.teachingenglish.org.uk/article/taboo-classroom
https://www.teachingenglish.org.uk/blogs/dario-banegas/teaching-english-through-controversial-topics